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AuthorTitleYearJournal/ProceedingsReftypeDOI/URL
Bühl, J., Babovsky, H., Kiessling, A. and Kowarschik, R. Digital synthesis of multiple off-axis holograms with overlapping Fourier spectra 2010 Opt. Commun.
Vol. 283(19), pp. 3631 - 3638 
article DOI URL 
Abstract: By applying tilted illumination on an object we record different sections of its Fourier spectrum in a row. We make use of an overlap between these sections to calculate their spatial frequency shift in sub-pixel accuracy by correlation methods. The global phase difference between the sections is corrected by subtracting the phase values of the overlapping areas and plotting them into a histogram. In this way the phase difference is measured with an accuracy of +- 0.10pi. Also the amplitude adjustment between different spectral sections is demonstrated. An experimental setup for synthetic aperture digital holography using tilted illumination is presented and a detailed description of the digital aperture synthesis is given. The method is applied to improve the resolution of a holographically recorded object.
BibTeX:
@article{Buehl2010,
  author = {J. Bühl and H. Babovsky and A. Kiessling and R. Kowarschik},
  title = {Digital synthesis of multiple off-axis holograms with overlapping Fourier spectra},
  journal = {Opt. Commun.},
  year = {2010},
  volume = {283},
  number = {19},
  pages = {3631 - 3638},
  url = {http://www.sciencedirect.com/science/article/B6TVF-508CGTY-1/2/19459325f15d67398fada9b9240fdad3},
  doi = {http://dx.doi.org/10.1016/j.optcom.2010.05.038}
}
Babovsky, H., Grosse, M., Buehl, J., Kiessling, A. and Kowarschik, R. Stereophotogrammetric 3D shape measurement by holographic methods using structured speckle illumination combined with interferometry 2011 Opt. Lett.
Vol. 36(23), pp. 4512-4514 
article DOI URL 
Abstract: We present a unique combination of the numerical three-dimensional (3D) reconstruction of the shape of an object with interferometric deformation measurements. Two cameras record several holograms of an object that is illuminated by structured illumination. This illumination is realized by speckle patterns. To improve the image quality, an inplace speckle reduction technique is combined with the structured illumination to reduce the effect of disturbing subjective speckles which appear in the reconstructed images. Stereophotogrammetric methods are applied to extract the 3D surface information of the object out of the reconstructed images. Since the recording is done by holography and because stereophotogrammetry enables a pointwise correlation between the two views, it is possible to combine other holographic techniques with the reconstructed 3D shape. This is demonstrated by an interferometric deformation measurement of an object cooling down. The resulting interferometric fringes are mapped onto the reconstructed 3D surface. Hence, the proposed method enables automatic and dense matching of interferometric fringe-maps recorded by spatially separated holograms onto the surface of the object, which has not yet been realized by existing techniques.
BibTeX:
@article{Babovsky2011,
  author = {Holger Babovsky and Marcus Grosse and Johannes Buehl and Armin Kiessling and Richard Kowarschik},
  title = {Stereophotogrammetric 3D shape measurement by holographic methods using structured speckle illumination combined with interferometry},
  journal = {Opt. Lett.},
  publisher = {OSA},
  year = {2011},
  volume = {36},
  number = {23},
  pages = {4512--4514},
  url = {http://ol.osa.org/abstract.cfm?URI=ol-36-23-4512},
  doi = {http://dx.doi.org/10.1364/OL.36.004512}
}
Brüning, R., Gelszinnis, P., Schulze, C., Flamm, D. and Duparré, M. Comparative analysis of numerical methods for the mode analysis of laser beams 2013 Appl. Opt.
Vol. 52(32), pp. 7769-7777 
article DOI URL 
Abstract: We present a comparative study of four numerical methods to detect the mode content of a laser beam from, at most, two intensity images. The techniques are compared regarding temporal effort, stability, and accuracy, using the example of three multimode optical fibers that differ in the number of supported modes.
BibTeX:
@article{Bruning2013,
  author = {Robert Brüning and Philipp Gelszinnis and Christian Schulze and Daniel Flamm and Michael Duparré},
  title = {Comparative analysis of numerical methods for the mode analysis of laser beams},
  journal = {Appl. Opt.},
  publisher = {OSA},
  year = {2013},
  volume = {52},
  number = {32},
  pages = {7769--7777},
  url = {http://ao.osa.org/abstract.cfm?URI=ao-52-32-7769},
  doi = {http://dx.doi.org/10.1364/AO.52.007769}
}
Flamm, D., Hou, K.-C., Gelszinnis, P., Schulze, C., Schröter, S. and Duparré, M. Modal characterization of fiber-to-fiber coupling processes 2013 Opt. Lett.
Vol. 38(12), pp. 2128-2130 
article DOI URL 
Abstract: We present a detailed experimental investigation of a fiber-to-fiber coupling process by characterizing the mode content at the output of the system. In our experiment a single-mode fiber is transversally scanned with respect to a multimode fiber, revealing position-dependent higher-order mode excitation. The outlined measurement system can be used for automated optimization of fundamental mode content and beam quality. Additionally, our approach characterizes the modal transmission properties of the multimode waveguide in its present state and is hence of high relevance for the conception of transport fibers and fiber laser systems.
BibTeX:
@article{Flamm2013a,
  author = {Daniel Flamm and Kai-Chung Hou and Philipp Gelszinnis and Christian Schulze and Siegmund Schröter and Michael Duparré},
  title = {Modal characterization of fiber-to-fiber coupling processes},
  journal = {Opt. Lett.},
  publisher = {OSA},
  year = {2013},
  volume = {38},
  number = {12},
  pages = {2128--2130},
  url = {http://ol.osa.org/abstract.cfm?URI=ol-38-12-2128},
  doi = {http://dx.doi.org/10.1364/OL.38.002128}
}
Flamm, D., Naidoo, D., Schulze, C., Forbes, A. and Duparré, M. Mode analysis with a spatial light modulator as a correlation filter 2012 Opt. Lett.
Vol. 37(13), pp. 2478-2480 
article DOI URL 
Abstract: A procedure for the real-time analysis of laser modes using a phase-only spatial light modulator is outlined. The procedure involves encoding into digital holograms by complex amplitude modulation a set of orthonormal basis functions into which the initial field is decomposed. This approach allows any function to be encoded and refreshed in real time (60Hz). We implement a decomposition of guided modes propagating in optical fibers and show that we can successfully reconstruct the observed field with very high fidelity.
BibTeX:
@article{Flamm2012b,
  author = {Daniel Flamm and Darryl Naidoo and Christian Schulze and Andrew Forbes and Michael Duparré},
  title = {Mode analysis with a spatial light modulator as a correlation filter},
  journal = {Opt. Lett.},
  publisher = {OSA},
  year = {2012},
  volume = {37},
  number = {13},
  pages = {2478--2480},
  url = {http://ol.osa.org/abstract.cfm?URI=ol-37-13-2478},
  doi = {http://dx.doi.org/10.1364/OL.37.002478}
}
Flamm, D., Schmidt, O.A., Schulze, C., Borchardt, J., Kaiser, T., Schröter, S. and Duparré, M. Measuring the spatial polarization distribution of multimode beams emerging from passive step-index large-mode-area fibers 2010 Opt. Lett.
Vol. 35(20), pp. 3429-3431 
article URL 
Abstract: We measure the polarization state of each guided transversal mode propagating in step-index large-mode-area fibers (V?4) using a correlation-filter based measurement technique in combination with a Stokes parameter measurement. The entire emerging beam, expressed in terms of a phase-dependent superposition of linearly polarized modes, demonstrates spatially varying polarization properties. By knowing the information about modal amplitudes and phase differences, full information about the optical field is available.
BibTeX:
@article{Flamm2010a,
  author = {Daniel Flamm and Oliver A. Schmidt and Christian Schulze and Julia Borchardt and Thomas Kaiser and Siegmund Schröter and Michael Duparré},
  title = {Measuring the spatial polarization distribution of multimode beams emerging from passive step-index large-mode-area fibers},
  journal = {Opt. Lett.},
  publisher = {OSA},
  year = {2010},
  volume = {35},
  number = {20},
  pages = {3429--3431},
  url = {http://ol.osa.org/abstract.cfm?URI=ol-35-20-3429}
}
Flamm, D., Schulze, C., Brüning, R., Schmidt, O.A., Kaiser, T., Schröter, S. and Duparré, M. Fast M2 measurement for fiber beams based on modal analysis 2012 Appl. Opt.
Vol. 51(7), pp. 987-993 
article DOI URL 
Abstract: We report on a fast and experimentally easy technique for measuring the beam propagation ratio M2 of light guided by optical fibers. A holographic filter enables us to determine amplitudes and phases of the excited fiber eigenmodes. The coherent superposition of modes allows the reconstruction of the optical field. With this information at hand, we are able to simulate the free-space propagation of the beam and to perform a virtual caustic measurement. Associated beam propagation ratios M2 accurately agree with ISO-standard measurements.
BibTeX:
@article{Flamm2012a,
  author = {Daniel Flamm and Christian Schulze and Robert Brüning and Oliver A. Schmidt and Thomas Kaiser and Siegmund Schröter and Michael Duparré},
  title = {Fast M2 measurement for fiber beams based on modal analysis},
  journal = {Appl. Opt.},
  publisher = {OSA},
  year = {2012},
  volume = {51},
  number = {7},
  pages = {987--993},
  url = {http://ao.osa.org/abstract.cfm?URI=ao-51-7-987},
  doi = {http://dx.doi.org/10.1364/AO.51.000987}
}
Flamm, D., Schulze, C., Naidoo, D., Schröter, S., Forbes, A. and Duparré, M. All-Digital Holographic Tool for Mode Excitation and Analysis in Optical Fibers 2013 J. Lightwave Technol.
Vol. 31(7), pp. 1023 -1032 
article DOI  
BibTeX:
@article{Flamm2013,
  author = {Flamm, D. and Schulze, C. and Naidoo, D. and Schröter, S. and Forbes, A. and Duparré, M.},
  title = {All-Digital Holographic Tool for Mode Excitation and Analysis in Optical Fibers},
  journal = {J. Lightwave Technol.},
  year = {2013},
  volume = {31},
  number = {7},
  pages = {1023 -1032},
  doi = {http://dx.doi.org/10.1109/JLT.2013.2240258}
}
Große, M., Schaffer, M., Harendt, B. and Kowarschik, R. Generalized phase evaluation for stereophotogrammetric correspondence assignment 2012 Opt. Lett.
Vol. 37(16), pp. 3468-3470 
article URL 
Abstract: Phase-shifting fringe projection is the primary structured illumination method for high-accuracy, three-dimensional (3D) shape measurements in the fields of profilometry and stereophotogrammetry. Many different schemes for the phase evaluation and the phase-shifted fringe pattern design exist. Here we focus on the role of the phase evaluation in the context of stereophotogrammetry, where the nominal phase value itself is merely used as an image feature that can be exploited to establish a correspondence between the two camera views. Starting from the classical phase evaluation function, we will discuss its essential properties for a highly accurate correspondence mapping. Based on the findings, we generalize the classical function to derive a generalized phase value for a sequence of stereo images. An experimental comparison between a correspondence assignment using the classical phase evaluation function and a specifically chosen general phase evaluation function is given.
BibTeX:
@article{Grosse2012,
  author = {Marcus Große and Martin Schaffer and Bastian Harendt and Richard Kowarschik},
  title = {Generalized phase evaluation for stereophotogrammetric correspondence assignment},
  journal = {Opt. Lett.},
  publisher = {OSA},
  year = {2012},
  volume = {37},
  number = {16},
  pages = {3468--3470},
  url = {http://ol.osa.org/abstract.cfm?URI=ol-37-16-3468}
}
Grosse, M., Buehl, J., Babovsky, H., Kiessling, A. and Kowarschik, R. 3D shape measurement of macroscopic objects in digital off-axis holography using structured illumination 2010 Opt. Lett.
Vol. 35(8), pp. 1233-1235 
article URL 
Abstract: We propose what we believe to be a novel approach to measure the 3D shape of arbitrary diffuse-reflecting macroscopic objects in holographic setups. Using a standard holographic setup, a second CCD and a liquid-crystal-on-silicon spatial light modulator to modulate the object wave, the method yields a dense 3D point cloud of an object or a scene. The calibration process is presented, and first quantitative results of a shape measurement are shown and discussed. Furthermore, a shape measurement of a complex object is displayed to demonstrate its universal use.
BibTeX:
@article{Grosse2010,
  author = {Marcus Grosse and Johannes Buehl and Holger Babovsky and Armin Kiessling and Richard Kowarschik},
  title = {3D shape measurement of macroscopic objects in digital off-axis holography using structured illumination},
  journal = {Opt. Lett.},
  publisher = {OSA},
  year = {2010},
  volume = {35},
  number = {8},
  pages = {1233--1235},
  url = {http://ol.osa.org/abstract.cfm?URI=ol-35-8-1233}
}
Grosse, M., Schaffer, M., Harendt, B. and Kowarschik, R. Camera calibration using time-coded planar patterns 2012 Opt. Eng.
Vol. 51(8), pp. 083604 
article DOI URL 
Abstract: In this paper a novel pattern design for camera calibration using planar patterns with the Zhang calibration method is presented. In contrast to other work related to this calibration technique, which deals with the design and extraction of spatial image features, our focus lies on the precise and fully automated extraction of corresponding points by temporal image features using a sequence of planar patterns, which are displayed by a flat screen. The extraction of correspondences in our approach does not utilize areal properties of the images and therefore is hardly influenced by projective distortion, image distortion, or inhomogeneous illumination. Furthermore, not the whole pattern but only parts of it need to be visible in an individual view. In addition, the planarity as well as the physical precision of the control points of the pattern are ensured by the very nature of the flat screen. The overall calibration time may be reduced, as no human interaction is necessary. We compare the results gained from this novel temporal pattern design with those gained from commonly used checkerboard patterns. The proposed approach resulted in an increased precision for the calibration.
BibTeX:
@article{grosse:083604,
  author = {Marcus Grosse and Martin Schaffer and Bastian Harendt and Richard Kowarschik},
  title = {Camera calibration using time-coded planar patterns},
  journal = {Opt. Eng.},
  publisher = {SPIE},
  year = {2012},
  volume = {51},
  number = {8},
  pages = {083604},
  url = {http://link.aip.org/link/?JOE/51/083604/1},
  doi = {http://dx.doi.org/10.1117/1.OE.51.8.083604}
}
Grosse, M., Schaffer, M., Harendt, B. and Kowarschik, R. Fast data acquisition for three-dimensional shape measurement using fixed-pattern projection and temporal coding 2011 Opt. Eng.
Vol. 50(10), pp. 100503 
article DOI  
Abstract: The field of image-based shape measurements using structured illumination has been an active research area for several decades now. A lot of different methods are widely used e.g. for industrial inspection, surveillance as well as multimedia purposes. Usually, short measurement times and high correspondence accuracy are mutually exclusive properties, due to the limitations of the used projection technology. Using a standard stereo-photogrammetry approach, as well as a simple, yet powerful structured light projection concept based on a slide-projector, we demonstrate an acquisition rate of more than 700 dense and accurate 3D measurements per second.
BibTeX:
@article{Grosse2011,
  author = {Grosse, M. and Schaffer, M. and Harendt, B. and Kowarschik, R.},
  title = {Fast data acquisition for three-dimensional shape measurement using fixed-pattern projection and temporal coding},
  journal = {Opt. Eng.},
  year = {2011},
  volume = {50},
  number = {10},
  pages = {100503},
  doi = {http://dx.doi.org/10.1117/1.3646100}
}
Jungnickel, H., Babovsky, H., Kiessling, A., Gebhardt, M., Grein, H.-J. and Kowarschik, R. Effects on Vision With Glare After Correction of Monochromatic Wavefront Aberrations 2011 J. Refractive Surgery
Vol. 27(8), pp. 602-612 
article DOI  
Abstract: Correction of aberrations up to the 6th Zernike order (closed-loop correction) was compared with conventional spectacle correction in 42 healthy eyes. To create these corrections, an adaptive optics system including a thin-film transistor (TFT) monitor for displaying optotypes with additional glare sources was used. Employing both corrections, visual acuity and contrast sensitivity (CS) were tested alternately with and without glare. Disability glare was computed as the difference between log CS without and with glare. Individuals were also asked to rate subjectively the quality of three images displayed on the TFT monitor.
BibTeX:
@article{Jungnickel2011,
  author = {H. Jungnickel and H. Babovsky and A. Kiessling and M. Gebhardt and H.-J. Grein and R. Kowarschik},
  title = {Effects on Vision With Glare After Correction of Monochromatic Wavefront Aberrations},
  journal = {J. Refractive Surgery},
  year = {2011},
  volume = {27},
  number = {8},
  pages = {602-612},
  doi = {http://dx.doi.org/10.3928/1081597X-20110317-02}
}
Kaiser, T., Flamm, D., Schröter, S. and Duparré, M. Complete modal decomposition for optical fibers using CGH-based correlation filters 2009 Opt. Express
Vol. 17(11), pp. 9347-9356 
article DOI URL 
Abstract: The description of optical fields in terms of their eigenmodes
is an intuitive approach for beam characterization. However, there is a
lack of unambiguous, pure experimental methods in contrast to numerical
phase-retrieval routines, mainly because of the difficulty to characterize
the phase structure properly, e.g. if it contains singularities. This paper
presents novel results for the complete modal decomposition of optical
fields by using computer-generated holographic filters. The suitability of
this method is proven by reconstructing various fields emerging from a
weakly multi-mode fiber (V approx. 5) with arbitrary mode contents. Advantages
of this approach are its mathematical uniqueness and its experimental
simplicity. The method constitutes a promising technique for real-time
beam characterization, even for singular beam profiles.
BibTeX:
@article{Kaiser2009,
  author = {Thomas Kaiser and Daniel Flamm and Siegmund Schröter and Michael Duparré},
  title = {Complete modal decomposition for optical fibers using CGH-based correlation filters},
  journal = {Opt. Express},
  publisher = {OSA},
  year = {2009},
  volume = {17},
  number = {11},
  pages = {9347--9356},
  url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-17-11-9347},
  doi = {http://dx.doi.org/10.1364/OE.17.009347}
}
Kashin, O., Tolstik, E., Matusevich, V. and Kowarschik, R. Numerical investigation of the (1$+$1)D self-trapping of laser beams in polymeric films based on polymethylmethacrylate and phenanthrenequinone 2009 J. Opt. Soc. Am. B
Vol. 26(11), pp. 2152-2156 
article URL 
Abstract: An analytical description connected with a numerical calculation of the propagation of self-trapped laser beams in a polymethylmethacrylate matrix containing phenanthrenequinone molecules is presented. A theoretical model for the spatial distribution of boundary optical waves is developed in dependence on characteristic beam parameters.
BibTeX:
@article{Kashin2009,
  author = {O. Kashin and E. Tolstik and V Matusevich and R. Kowarschik},
  title = {Numerical investigation of the (1$+$1)D self-trapping of laser beams in polymeric films based on polymethylmethacrylate and phenanthrenequinone},
  journal = {J. Opt. Soc. Am. B},
  publisher = {OSA},
  year = {2009},
  volume = {26},
  number = {11},
  pages = {2152--2156},
  url = {http://josab.osa.org/abstract.cfm?URI=josab-26-11-2152}
}
Khmelnitsky, D., Matusevich, V., Kiessling, A., Kowarschik, R., Ryzhova, V., V.Shepelevich and A.Zagorsky Interaction of two-dimensional rectangular light beams in photorefractive SBN crystal 2009 Ferroelectrics 390
Vol. 18 
article URL 
Abstract: The interaction of rectangular light beams is studied in a SBN crystal of 2 cm length. It is shown that two beams with a rectangular cross section of 30 times 30 $m2 and with a distance of 60 $m between them, oriented perpendicular to an external electric field E0 = 3 kV/cm fuse into one beam. The same beams arranged parallel to the external electric field do not fuse. It is found that using the diffusion term of the potential equation we can explain the asymmetric behavior of the light beams, which are arranged parallel to the external electric field. It is observed that using four propagating beams leads to stabilization of the quasi-soliton formation.
BibTeX:
@article{Khmelnitsky2009,
  author = {D. Khmelnitsky and V. Matusevich and A. Kiessling and R. Kowarschik and V. Ryzhova and V.Shepelevich and A.Zagorsky},
  title = {Interaction of two-dimensional rectangular light beams in photorefractive SBN crystal},
  journal = {Ferroelectrics 390},
  year = {2009},
  volume = {18},
  url = {http://www.informaworld.com/smpp/content~db=all~content=a927118277}
}
Liu, S., Gleeson, M.R., Guo, J., Sheridan, J.T., Tolstik, E., Matusevich, V. and Kowarschik, R. Modeling the photochemical kinetics induced by holographic exposures in PQ/PMMA photopolymer material 2011 J. Opt. Soc. Am. B
Vol. 28(11), pp. 2833-2843 
article DOI URL 
Abstract: Phenanthrenequinone (PQ) doped poly(methyl methacrylate) (PMMA) photopolymer material is receiving ever greater attention in the literature due to its attractive properties for applications such as holographic data storage, hybrid optoelectronics, solar concentrators, self-trapping of light, and diffractive optical elements. PQ/PMMA photopolymer material can be used to produce three-dimensional low loss, low shrinkage recordings that are environmentally stable, have high contrast refractive index variations, and can produce high-optical-quality devices. However, in any attempt to further develop the potential of such materials, a more physical and accurate theoretical model has become ever more necessary and important. In this paper, based on a detailed analysis of the photochemical mechanisms present in PQ/PMMA photopolymer during holographic grating formation, a set of rate equations are derived governing the temporal and spatial variations of each associated chemical species concentration. Experimental results are presented, which are then fit using this model. In this way, values for several kinetic parameters are estimated and their significance is discussed.
BibTeX:
@article{Liu2011,
  author = {Shui Liu and Michael R. Gleeson and Jinxin Guo and John T. Sheridan and Elen Tolstik and Vladislav Matusevich and Richard Kowarschik},
  title = {Modeling the photochemical kinetics induced by holographic exposures in PQ/PMMA photopolymer material},
  journal = {J. Opt. Soc. Am. B},
  publisher = {OSA},
  year = {2011},
  volume = {28},
  number = {11},
  pages = {2833--2843},
  url = {http://josab.osa.org/abstract.cfm?URI=josab-28-11-2833},
  doi = {http://dx.doi.org/10.1364/JOSAB.28.002833}
}
Matusevich, A., Tolstik, A., Kisteneva, M., Shandarov, S., Matusevich, V., Kiessling, A. and Kowarschik, R. Methods for controlling of the laser-induced absorption in a BTO crystal by using of cw-laser radiation 2009 Applied Physics B: Lasers and Optics
Vol. 96(1), pp. 119-125 
article URL 
Abstract: A photorefractive BTO crystal is exposed with cw-laser beams (430 mW/cm2 at 514 nm), and the photo-induced absorption between 480 and 900 nm is studied. A method of controlling this absorption by low intensity laser radiation of green and red wavelengths is demonstrated. The physical mechanism can be explained by the redistribution of electrons on the long-lived energy levels into the forbidden band. Dynamical characteristics of the redistribution are estimated.
BibTeX:
@article{Matusevich2009,
  author = {Matusevich, A. and Tolstik, A. and Kisteneva, M. and Shandarov, S. and Matusevich, V. and Kiessling, A. and Kowarschik, R.},
  title = {Methods for controlling of the laser-induced absorption in a BTO crystal by using of cw-laser radiation},
  journal = {Applied Physics B: Lasers and Optics},
  publisher = {Springer Berlin / Heidelberg},
  year = {2009},
  volume = {96},
  number = {1},
  pages = {119--125},
  url = {http://dx.doi.org/10.1007/s00340-009-3512-1}
}
Matusevich, V., Tolstik, E., Winkler, A. and Kowarschik, R. Head-Up-Display auf Plexiglasbasis 2010 Photonik 2
Vol. 44, pp. 44-45 
article URL 
Abstract: Effiziente Reflexionen zur Informationsdarstellung in Head-Up-Displays (HUD) knnen mittels eines Phasen-Volumen-Hologramms in einer Photopolymerschicht erzeugt werden. Durch den Einsatz eines neu entwickelten, PMMA und AA basierenden Photopolymers kann der Beugungswirkungsgrad erhht, sowie der Spektralbrereich des einfallenden Lichtes verbreitert werden.
BibTeX:
@article{V.Matusevich2010,
  author = {V. Matusevich and E. Tolstik and A. Winkler and R. Kowarschik},
  title = {Head-Up-Display auf Plexiglasbasis},
  journal = {Photonik 2},
  year = {2010},
  volume = {44},
  pages = {44-45},
  url = {http://www.google.de/url?sa=t&source=web&cd=1&ved=0CBoQFjAA&url=http%3A%2F%2Fwww.photonik.de%2Findex.php%3Fid%3D112%26seitenid%3D11%26fachid%3D785%26readpdf%3Dphotonik_2010_02_044.pdf&rct=j&q=V.%20Matusevich%2C%20E.%20Tolstik%2C%20A.%20Winkler%2C%20R.%20Kowarschik%2C%20Head-Up-Display%20auf%20plexiglasbasis%2C%20Photonik%202%2C%2044%20(2010)&ei=dom1TJPGI4uXOsvM5JUG&usg=AFQjCNFv18CuPICHS2Q5GyTiWetm6qeWaw&sig2=BaTsKObromwdlImDRLOUwA&cad=rja}
}
Schaffer, M., Große, M., Harendt, B. and Kowarschik, R. Coherent two-beam interference fringe projection for highspeed three-dimensional shape measurements 2013 Appl. Opt.
Vol. 52(11), pp. 2306-2311 
article URL 
Abstract: Two-beam interference is a fundamental and well-understood approach to create Fizeau&x2019;s interference fringes. With a Mach&x2013;Zehnder interferometer, we utilize these two-beam interference Fizeau fringes for three-dimensional (3D) shape measurements. By introducing an acousto-optical deflector the phase of the interference fringes can be shifted with a rate of up to 20,000&xA0;Hz. When used in conjunction with highspeed cameras, this stereo-photogrammetric approach performs well for highspeed applications in comparison with the commonly used digital light processing projectors for stripe projection. Maximum speed and the achievable accuracy are discussed. Experiments and media substantiate the suitability, accuracy, and speed of this technique for very fast 3D shape measurements.
BibTeX:
@article{Schaffer2013,
  author = {Martin Schaffer and Marcus Große and Bastian Harendt and Richard Kowarschik},
  title = {Coherent two-beam interference fringe projection for highspeed three-dimensional shape measurements},
  journal = {Appl. Opt.},
  publisher = {OSA},
  year = {2013},
  volume = {52},
  number = {11},
  pages = {2306--2311},
  url = {http://ao.osa.org/abstract.cfm?URI=ao-52-11-2306}
}
Schaffer, M., Große, M., Harendt, B. and Kowarschik, R. High-Speed Optical 3-D Measurements for Shape Representation 2011 Opt. Photon. News
Vol. 22(12), pp. 49-49 
article DOI URL 
Abstract: The display of 3-D objects has always been fascinating. Recent researchexplores new possibilities in holographic imaging and 3-D television.
BibTeX:
@article{Schaffer2011c,
  author = {Martin Schaffer and Marcus Große and Bastian Harendt and Richard Kowarschik},
  title = {High-Speed Optical 3-D Measurements for Shape Representation},
  journal = {Opt. Photon. News},
  publisher = {OSA},
  year = {2011},
  volume = {22},
  number = {12},
  pages = {49--49},
  url = {http://www.osa-opn.org/abstract.cfm?URI=opn-22-12-49},
  doi = {http://dx.doi.org/10.1364/OPN.22.12.000049}
}
Schaffer, M., Grosse, M., Harendt, B. and Kowarschik, R. High-speed three-dimensional shape measurements of objects with laser speckles and acousto-optical deflection 2011 Opt. Lett.
Vol. 36(16), pp. 3097-3099 
article DOI URL 
Abstract: Many three-dimensional (3D) shape measurement techniques in stereophotogrammetry with temporal coded structured illumination are limited to static scenes because the time for measurement is too long in comparison to the object speed. The measurement of moving objects result in erroneous reconstructions. This is apparent to reduce measurement time to overcome this limitation, which is often done by increasing the projection rate for illumination while shrinking the amount of images taken for reconstruction. The projection rate limits most applications in its speed because digital light processing (DLP) projectors, which are widely used, bring a limited projection rate along. Our approach, in contrast, does not take a DLP. Instead we use laser speckles as projected patterns which are switched using an acousto-optical deflector. The projection rate is 10texttimes higher than what the fastest stripe projection systems to our knowledge achieve. Hence, we present this uncommon but potential approach for highspeed ($250?3Dfps$=$ 3D measurements per second), dense, and accurate 3D measurements of spatially separated objects and show the media that emphasizes the ability of accurate measurements while the objects under testing move.
BibTeX:
@article{Schaffer2011b,
  author = {Martin Schaffer and Marcus Grosse and Bastian Harendt and Richard Kowarschik},
  title = {High-speed three-dimensional shape measurements of objects with laser speckles and acousto-optical deflection},
  journal = {Opt. Lett.},
  publisher = {OSA},
  year = {2011},
  volume = {36},
  number = {16},
  pages = {3097--3099},
  url = {http://ol.osa.org/abstract.cfm?URI=ol-36-16-3097},
  doi = {http://dx.doi.org/10.1364/OL.36.003097}
}
Schaffer, M., Groe, M., Harendt, B. and Kowarschik, R. Outdoor three-dimensional shape measurements using laser-based structured illumination 2012 Opt. Eng.
Vol. 51(9), pp. 090503-1-090503-3 
article DOI URL 
Abstract: Three-dimensional shape measurements using structured illumination can achieve accurate shape representation of arbitrary object scenes. High-speed approaches have been recently developed and are already on the way into industry. Structured illumination for outdoor applications is rarely used as it is difficult to achieve a high-pattern contrast under bright light conditions. Hence, laser scanning or photogrammetry without active illumination is usually preferred; often, measurements are carried out at night. A shape measurement approach is suggested, one that is suitable to quickly and accurately acquire object shapes, even under difficult light circumstances. This approach is based on laser speckle projection and spectral filtering. The results made with this setup are presented, along with media that underlines its capabilities.
BibTeX:
@article{Schaffer2012,
  author = {Schaffer, Martin and Groe, Marcus and Harendt, Bastian and Kowarschik, Richard},
  title = {Outdoor three-dimensional shape measurements using laser-based structured illumination},
  journal = {Opt. Eng.},
  year = {2012},
  volume = {51},
  number = {9},
  pages = {090503-1-090503-3},
  url = { + http://dx.doi.org/10.1117/1.OE.51.9.090503},
  doi = {http://dx.doi.org/10.1117/1.OE.51.9.090503}
}
Schaffer, M., Grosse, M. and Kowarschik, R. High-speed pattern projection for three-dimensional shape measurement using laser speckles 2010 Appl. Opt.
Vol. 49(18), pp. 3622-3629 
article URL 
Abstract: We propose a high-speed projection system that is able to project statistical speckle patterns at a rate of 500Hz. Its purpose is to generate structured light for a real-time photogrammetry stereo vision setup. As conventional digital light projector (DLP) projection setups are limited in their maximum projection rate to 250Hz for gray-value patterns, stripe projection systems are usually applied for real-time three-dimensional (3D) measurements. However, these techniques can only be used on steady surfaces as phase unwrapping has to be done. In contrast, the proposed setup is able to measure the shape of multiple spatially separated objects at once. We compare the speckle setup with a system using a DLP projector and with other fast 3D shape measurement setups, like the widely used stripe projection methods, qualitatively and quantitatively.
BibTeX:
@article{Schaffer2010,
  author = {Martin Schaffer and Marcus Grosse and Richard Kowarschik},
  title = {High-speed pattern projection for three-dimensional shape measurement using laser speckles},
  journal = {Appl. Opt.},
  publisher = {OSA},
  year = {2010},
  volume = {49},
  number = {18},
  pages = {3622--3629},
  url = {http://ao.osa.org/abstract.cfm?URI=ao-49-18-3622}
}
Schmidt, O.A., Schulze, C., Flamm, D., Brüning, R., Kaiser, T., Schröter, S. and Duparré, M. Real-time determination of laser beam quality by modal decomposition 2011 Opt. Express
Vol. 19(7), pp. 6741-6748 
article DOI URL 
Abstract: We present a real-time method to determine the beam propagation ratio M2 of laser beams. The all-optical measurement of modal amplitudes yields M2 parameters conform to the ISO standard method. The experimental technique is simple and fast, which allows to investigate laser beams under conditions inaccessible to other methods.
BibTeX:
@article{Schmidt2011,
  author = {Oliver A. Schmidt and Christian Schulze and Daniel Flamm and Robert Brüning and Thomas Kaiser and Siegmund Schröter and Michael Duparré},
  title = {Real-time determination of laser beam quality by modal decomposition},
  journal = {Opt. Express},
  publisher = {OSA},
  year = {2011},
  volume = {19},
  number = {7},
  pages = {6741--6748},
  url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-19-7-6741},
  doi = {http://dx.doi.org/10.1364/OE.19.006741}
}
Schulze, C., Dudley, A., Flamm, D., Duparré, M. and Forbes, A. Reconstruction of laser beam wavefronts based on mode analysis 2013 Appl. Opt.
Vol. 52(21), pp. 5312-5317 
article DOI URL 
Abstract: We present the reconstruction of a laser beam wavefront from its mode spectrum and investigate in detail the impact of distinct aberrations on the mode composition. The measurement principle is presented on a Gaussian beam that is intentionally distorted by displaying defined aberrations on a spatial light modulator. The comparison of reconstructed and programmed wavefront aberrations yields excellent agreement, proving the high measurement fidelity.
BibTeX:
@article{Schulze2013a,
  author = {Christian Schulze and Angela Dudley and Daniel Flamm and Michael Duparré and Andrew Forbes},
  title = {Reconstruction of laser beam wavefronts based on mode analysis},
  journal = {Appl. Opt.},
  publisher = {OSA},
  year = {2013},
  volume = {52},
  number = {21},
  pages = {5312--5317},
  url = {http://ao.osa.org/abstract.cfm?URI=ao-52-21-5312},
  doi = {http://dx.doi.org/10.1364/AO.52.005312}
}
Schulze, C., Dudley, A., Flamm, D., Duparré, M. and Forbes, A. Measurement of the orbital angular momentum density of light by modal decomposition 2013 New J. Phys.
Vol. 15(7), pp. 073025 
article URL 
Abstract: We demonstrate a versatile method for the measurement of the orbital angular momentum (OAM) density of an optical field. By performing a modal decomposition with digital holograms, we reconstruct the full optical field from a small set of single-point intensity measurements, from which optical vortices, global OAM and OAM density can be derived. We validate the method on defined OAM-carrying beams yielding fidelities in the OAM density measurement of up to 99%, and subsequently apply the technique to unknown fields from optical fibers.
BibTeX:
@article{Schulze2013f,
  author = {Christian Schulze and Angela Dudley and Daniel Flamm and Michael Duparré and Andrew Forbes},
  title = {Measurement of the orbital angular momentum density of light by modal decomposition},
  journal = {New J. Phys.},
  year = {2013},
  volume = {15},
  number = {7},
  pages = {073025},
  url = {http://stacks.iop.org/1367-2630/15/i=7/a=073025}
}
Schulze, C., Flamm, D., Duparré, M. and Forbes, A. Beam-quality measurements using a spatial light modulator 2012 Opt. Lett.
Vol. 37(22), pp. 4687-4689 
article URL 
Abstract: We present a fast and easy technique for measuring the beam propagation ratio, M2, of laser beams using a spatial light modulator. Our technique is based on digitally simulating the free-space propagation of light, thus eliminating the need for the traditional scan in the propagation direction. We illustrate two approaches to achieving this, neither of which requires any information of the laser beam under investigation nor necessitates any moving optical components. The comparison with theoretical predictions reveals excellent agreement and proves the accuracy of the technique.
BibTeX:
@article{Schulze:12,
  author = {Christian Schulze and Daniel Flamm and Michael Duparré and Andrew Forbes},
  title = {Beam-quality measurements using a spatial light modulator},
  journal = {Opt. Lett.},
  publisher = {OSA},
  year = {2012},
  volume = {37},
  number = {22},
  pages = {4687--4689},
  url = {http://ol.osa.org/abstract.cfm?URI=ol-37-22-4687}
}
Schulze, C., Flamm, D., Unger, S., Schröter, S. and Duparré, M. Measurement of higher-order mode propagation losses in effectively single mode fibers 2013 Opt. Lett.
Vol. 38(23), pp. 4958-4961 
article DOI URL 
Abstract: We present a direct and nondestructive measurement of the propagation loss of higher-order modes (HOMs) in effectively single-mode fibers. Lossy HOMs are excited by applying local stress at various points alongside a straight single mode fiber. The change of the HOM power as a function of the propagation distance is recorded at the fiber end by performing a modal decomposition with a correlation filter. The results for the HOM propagation loss are compared to simulations yielding very good agreement.
BibTeX:
@article{Schulze2013e,
  author = {Christian Schulze and Daniel Flamm and Sonja Unger and Siegmund Schröter and Michael Duparré},
  title = {Measurement of higher-order mode propagation losses in effectively single mode fibers},
  journal = {Opt. Lett.},
  publisher = {OSA},
  year = {2013},
  volume = {38},
  number = {23},
  pages = {4958--4961},
  url = {http://ol.osa.org/abstract.cfm?URI=ol-38-23-4958},
  doi = {http://dx.doi.org/10.1364/OL.38.004958}
}
Schulze, C., Lorenz, A., Flamm, D., Hartung, A., Schröter, S., Bartelt, H. and Duparré, M. Mode resolved bend loss in few-mode optical fibers 2013 Opt. Express
Vol. 21(3), pp. 3170-3181 
article DOI URL 
Abstract: We present a novel approach to directly measure the bend loss of individual modes in few-mode fibers based on the correlation filter technique. This technique benefits from a computer-generated hologram performing a modal decomposition, yielding the optical power of all propagating modes in the bent fiber. Results are compared with rigorous loss simulations and with common loss formulas for step-index fibers revealing high measurement fidelity. To the best of our knowledge, we demonstrate for the first time an experimental loss discrimination between index-degenerated modes.
BibTeX:
@article{Schulze2013,
  author = {Christian Schulze and Adrian Lorenz and Daniel Flamm and Alexander Hartung and Siegmund Schröter and Hartmut Bartelt and Michael Duparré},
  title = {Mode resolved bend loss in few-mode optical fibers},
  journal = {Opt. Express},
  publisher = {OSA},
  year = {2013},
  volume = {21},
  number = {3},
  pages = {3170--3181},
  url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-21-3-3170},
  doi = {http://dx.doi.org/10.1364/OE.21.003170}
}
Schulze, C., Naidoo, D., Flamm, D., Schmidt, O.A., Forbes, A. and Duparré, M. Wavefront reconstruction by modal decomposition 2012 Opt. Express
Vol. 20(18), pp. 19714-19725 
article DOI URL 
Abstract: We propose a new method to determine the wavefront of a laser beam based on modal decomposition by computer-generated holograms. The hologram is encoded with a transmission function suitable for measuring the amplitudes and phases of the modes in real-time. This yields the complete information about the optical field, from which the Poynting vector and the wavefront are deduced. Two different wavefront reconstruction options are outlined: reconstruction from the phase for scalar beams, and reconstruction from the Poynting vector for inhomogeneously polarized beams. Results are compared to Shack-Hartmann measurements that serve as a reference and are shown to reproduce the wavefront and phase with very high fidelity.
BibTeX:
@article{Schulze2012,
  author = {Christian Schulze and Darryl Naidoo and Daniel Flamm and Oliver A. Schmidt and Andrew Forbes and Michael Duparré},
  title = {Wavefront reconstruction by modal decomposition},
  journal = {Opt. Express},
  publisher = {OSA},
  year = {2012},
  volume = {20},
  number = {18},
  pages = {19714--19725},
  url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-20-18-19714},
  doi = {http://dx.doi.org/10.1364/OE.20.019714}
}
Schulze, C., Ngcobo, S., Duparré, M. and Forbes, A. Modal decomposition without a priori scale information 2012 Opt. Express
Vol. 20(25), pp. 27866-27873 
article DOI URL 
Abstract: The modal decomposition of an arbitrary optical field may be done without regard to the spatial scale of the chosen basis functions, but this generally leads to a large number of modes in the expansion. While this may be considered as mathematically correct, it is not efficient and not physically representative of the underlying field. Here we demonstrate a modal decomposition approach that requires no a priori knowledge of the spatial scale of the modes, but nevertheless leads to an optimised modal expansion. We illustrate the power of the method by successfully decomposing beams from a diode-pumped solid state laser resonator into an optimised Laguerre-Gaussian mode set. Our experimental results, which are in agreement with theory, illustrate the versatility of the approach.
BibTeX:
@article{Schulze2012d,
  author = {Christian Schulze and Sandile Ngcobo and Michael Duparré and Andrew Forbes},
  title = {Modal decomposition without a priori scale information},
  journal = {Opt. Express},
  publisher = {OSA},
  year = {2012},
  volume = {20},
  number = {25},
  pages = {27866--27873},
  url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-20-25-27866},
  doi = {http://dx.doi.org/10.1364/OE.20.027866}
}
Schwede, R., Babovsky, H., Kiessling, A. and Kowarschik, R. Measurement of three-dimensional deformation vectors with digital holography and stereophotogrammetry 2012 Opt. Lett.
Vol. 37(11), pp. 1943-1945 
article DOI URL 
Abstract: We present a method to determine the three-dimensional (3D) deformation vectors of an arbitrary stressed object by combining stereophotogrammetry and digital holography in a setup with four cameras. The resulting data consists of a dense 3D point cloud, where every point is associated with a deformation vector. Our method is able to calculate the deformation without prior knowledge of the sensitivity vectors or the object surface. In the experimental setup only the base distance of the cameras needs to be known.
BibTeX:
@article{Schwede2012,
  author = {Robert Schwede and Holger Babovsky and Armin Kiessling and Richard Kowarschik},
  title = {Measurement of three-dimensional deformation vectors with digital holography and stereophotogrammetry},
  journal = {Opt. Lett.},
  publisher = {OSA},
  year = {2012},
  volume = {37},
  number = {11},
  pages = {1943--1945},
  url = {http://ol.osa.org/abstract.cfm?URI=ol-37-11-1943},
  doi = {http://dx.doi.org/10.1364/OL.37.001943}
}
Tolstik, E., Egorova, E., Hoff, D., Matusevich, V., Yakimtsova, L., Matusevich, Y., Kowarschik, R. and Krul, L. New thermostable copolymers for holographic storage based on methylmethacrylate with methacrylamide or methacrylic acid 2012 J. Polymer Research
Vol. 19, pp. 1-9 
article DOI URL 
Abstract: Two new copolymers based on methylmethacrylate (MMA) with methacrylamide (MAA) and methacrylic acid (MA) containing distributed phenanthrenequinone (PQ) molecules are fabricated for the purpose of optical recording by generating holographic diffractive structures under argon laser illumination. Chemical conditions for the formation of holograms are discussed and confirmed by the spectral characteristics of the material. Thermal and adhesive properties were improved with the aim of expanding the range of polymer application and generating of diffractive elements with long term stability and high optical quality.
BibTeX:
@article{Tolstik2012,
  author = {Tolstik, Elen and Egorova, Elena and Hoff, Dominik and Matusevich, Vladislav and Yakimtsova, LudmilaB. and Matusevich, YuriI. and Kowarschik, Richard and Krul, LeonidP.},
  title = {New thermostable copolymers for holographic storage based on methylmethacrylate with methacrylamide or methacrylic acid},
  journal = {J. Polymer Research},
  publisher = {Springer Netherlands},
  year = {2012},
  volume = {19},
  pages = {1-9},
  url = {http://dx.doi.org/10.1007/s10965-011-9742-z},
  doi = {http://dx.doi.org/10.1007/s10965-011-9742-z}
}
Tolstik, E., Kashin, O., Matusevich, A., Matusevich, V., Kowarschik, R., Matusevich, Y.I. and Krul, L.P. Non-local response in glass-like polymer storage materials based on poly (methylmethacrylate) with distributed phenanthrenequinone 2008 Opt. Express
Vol. 16(15), pp. 11253-11258 
article DOI URL 
Abstract: The development of volume phase gratings written by two-wave-mixing in glass-like polymer storage materials based on poly (methylmethacrylate) and its thermostable derivative (copolymer with acrylic acid) with distributed phenanthrenequinone is investigated experimentally and theoretically. The maximal diffraction efficiency is considered in dependence on the grating period. The redistribution processes of the molecules are described with a one-dimensional diffusion model yielding the existence of a non-local response in the photopolymer layer, and the corresponding non-local response length of phenanthrenequinone is found experimentally.
BibTeX:
@article{Tolstik2008,
  author = {E. Tolstik and O. Kashin and A. Matusevich and V. Matusevich and R. Kowarschik and Yu. I. Matusevich and L. P. Krul},
  title = {Non-local response in glass-like polymer storage materials based on poly (methylmethacrylate) with distributed phenanthrenequinone},
  journal = {Opt. Express},
  publisher = {OSA},
  year = {2008},
  volume = {16},
  number = {15},
  pages = {11253--11258},
  url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-16-15-11253},
  doi = {http://dx.doi.org/10.1364/OE.16.011253}
}
Tolstik, E., Kashin, O., Matusevich, V. and Kowarschik, R. Broadening of the light self-trapping due to thermal defocusing in PQ-PMMA polymeric layers 2011 Opt. Express
Vol. 19(3), pp. 2739-2747 
article DOI URL 
Abstract: The channel formation by the self-trapping of a (1 $+$ 1)D beam in polymeric media based on a polymethylmethacrylate (PMMA) matrix containing phenanthrenequinone (PQ) molecules is predicted theoretically and observed experimentally for the first time. Particular attention is paid to the effect of thermal beam expansion, which in conjunction with the photorefractive nonlinearity of the medium results in the possibility to control optically the geometrical parameters of the generated channel.
BibTeX:
@article{Tolstik2011,
  author = {E. Tolstik and O. Kashin and V. Matusevich and R. Kowarschik},
  title = {Broadening of the light self-trapping due to thermal defocusing in PQ-PMMA polymeric layers},
  journal = {Opt. Express},
  publisher = {OSA},
  year = {2011},
  volume = {19},
  number = {3},
  pages = {2739--2747},
  url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-19-3-2739},
  doi = {http://dx.doi.org/10.1364/OE.19.002739}
}
Tolstik, E., Winkler, A., Matusevich, V., Kowarschik, R., Mahilny, U., Marmysh, D., Matusevich, Y. and Krul, L. PMMA-PQ Photopolymers for Head-Up-Displays 2009 Photon. Technol. Lett.
Vol. 21(12), pp. 784 -786 
article DOI  
Abstract: We present the experimental realization of a head-up-display based on a photopolymer. A phase volume reflection hologram is written in a photopolymer layer and is used as a screen for a signal beam. To write efficient holograms in the polymeric material we used ordinary and modified polymethylmethacrylate matrices containing phenanthrenequinone (PQ). Increasing the PQ concentration gives us an opportunity to realize thinner layers ( lt;100 mum) saving high values of the diffraction efficiency. Decreasing the thickness of the layer allows higher observation angles of the received image and a wider spectral range of the incident light.
BibTeX:
@article{Tolstik2009,
  author = {Tolstik, E. and Winkler, A. and Matusevich, V. and Kowarschik, R. and Mahilny, U.V. and Marmysh, D.N. and Matusevich, Y.I. and Krul, L.P.},
  title = {PMMA-PQ Photopolymers for Head-Up-Displays},
  journal = {Photon. Technol. Lett.},
  year = {2009},
  volume = {21},
  number = {12},
  pages = {784 -786},
  doi = {http://dx.doi.org/10.1109/LPT.2009.2018133}
}
Weigel, D., Babovsky, H., Kiessling, A. and Kowarschik, R. Investigation of the resolution ability of an image inversion interferometer 2011 Opt. Commun.
Vol. 284, pp. 22732277 
article DOI URL 
Abstract: The present paper presents the experimental measurement of the interferometric point spread function of an image inversion interferometer (III). The measurement was realized by scanning a pointlike source in the object plane and integrating the intensity in the image plane for each position of the point source. The achieved results are compared to the theoretical expectations and the results, which we received in a previous work by using a different method. The improved resolution of two neighbouring points in comparison to the conventional image is demonstrated. In addition we propose an explanation concerning the divergences of the values to be expected in theory.
BibTeX:
@article{Weigel2011,
  author = {D. Weigel and H. Babovsky and A. Kiessling and R. Kowarschik},
  title = {Investigation of the resolution ability of an image inversion interferometer},
  journal = {Opt. Commun.},
  year = {2011},
  volume = {284},
  pages = {22732277},
  url = {http://www.sciencedirect.com/science/article/pii/S0030401810014203},
  doi = {http://dx.doi.org/10.1016/j.optcom.2010.12.068}
}
Weigel, D., Babovsky, H., Kiessling, A. and Kowarschik, R. Investigation of the impulse response of an image inversion interferometer 2010 Opt. Commun.
Vol. 283(3), pp. 368 - 372 
article DOI URL 
Abstract: Based on the proposal of Wicker and Heintzmann #Interferometric##resolution##improvement##for##confocal##microscopes# [1] we demonstrate in principle the functionality of an image inversion interferometer (III) experimentally, which can be described by an appropriate frequency transfer function. Thereby, the FWHM of the impulse response narrows around 30% compared to the PSF of a classical system. The experimental data yield a FWHM of the impulse response of 0.83[mu]m as compared to the theoretical value of 1.21[mu]m at by a wide field detection (NA=0.25) without an interferometer.
BibTeX:
@article{Weigel2010,
  author = {D. Weigel and H. Babovsky and A. Kiessling and R. Kowarschik},
  title = {Investigation of the impulse response of an image inversion interferometer},
  journal = {Opt. Commun.},
  year = {2010},
  volume = {283},
  number = {3},
  pages = {368 - 372},
  url = {http://www.sciencedirect.com/science/article/B6TVF-4XHSHDC-5/2/150d76c4ce6d05b0056fc098383f16dd},
  doi = {http://dx.doi.org/10.1016/j.optcom.2009.10.013}
}
Weigel, D., Foerster, R., Babovsky, H., Kiessling, A. and Kowarschik, R. Enhanced resolution of microscopic objects by image inversion interferometry 2011 Opt. Express
Vol. 19(27), pp. 26451-26462 
article DOI URL 
Abstract: We demonstrate in experiment that the resolution of a conventional light microscope can be enhanced by 26% with the help of an image inverting interferometer. In order to prove this statement, we measured the point spread function of the system as well as the resolution of two-point objects. Additionally, the contrast transmission function of the interferometric setup was measured and compared to the results gained with a conventional wide-field microscope. Using the interferometric system, the spatial frequencies near the cutoff-frequency were far better transmitted than by the conventional microscope. Finally, we demonstrate the improved resolution with the help of images of two-dimensional structures.
BibTeX:
@article{Weigel2011a,
  author = {D. Weigel and R. Foerster and H. Babovsky and A. Kiessling and R. Kowarschik},
  title = {Enhanced resolution of microscopic objects by image inversion interferometry},
  journal = {Opt. Express},
  publisher = {OSA},
  year = {2011},
  volume = {19},
  number = {27},
  pages = {26451--26462},
  url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-19-27-26451},
  doi = {http://dx.doi.org/10.1364/OE.19.026451}
}