Aberration compensation using a spatial light modulator LCD

Author(s): R. Amézquita, O. Rincón and Y. M. Torres

Abstract:

“The dynamic correction of aberrations introduced in optical systems have been a widely discussed topic in the past 10 years. Adaptive optics is the most important developed field where the Shack-Hartmann sensors and deformable mirrors are used for the measurement and correction of wavefronts. In this paper, an interferometric set-up which uses a Spatial Light Modulator (SLM) as an active element is proposed. Using this SLM a procedure for the compensation of all phase aberrations present in the experimental setup is shown.”

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Publication: Journal of Physics: Conference Series, (free download)

Issue/Year/DOI: J. Phys.: Conf. Ser. 274 012111 (2011)
doi:10.1088/1742-6596/274/1/012111

Frequency bandwidth of light focused through turbid media

Author(s): Frerik van Beijnum, Elbert G. van Putten, Ad Lagendijk, and Allard P. Mosk

Abstract:

“We study the effect of frequency detuning on light focused through turbid media. By shaping the wavefront of the incident beam light is focused through an opaque scattering layer. When detuning the laser we observe a gradual decrease of the focus intensity, while the position, size,and shape of the focus remain the same within experimental accuracy. The frequency dependence of the focus intensity follows a measured speckle correlation function. We support our experimental findings with calculations based on transport theory. Our results imply wavefront shaping methods can be generalized to allow focusing of optical pulses in turbid media.”

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Publication: Optics Letters, (subscription required)

Issue/Year/DOI: Optics Letters, Vol. 36, Issue 3, pp. 373-375 (2011)
doi:10.1364/OL.36.000373

What spatial light modulators can do for optical microscopy

Author(s): C. Maurer, A. Jesacher, S. Bernet, M. Ritsch-Marte.

Abstract:

“With the availability of high-resolution miniature spatial light modulators (SLMs) new methods in optical microscopy have become feasible. The SLMs discussed in this review consist of miniature liquid crystal displays with micron-sized pixels that can modulate the phase and/or amplitude of an optical wavefront. In microscopy they can be used to control and shape the sample illumination, or they can act as spatial Fourier filters in the imaging path. Some of these applications are reviewed in this article. One of them, called spiral phase contrast, generates isotropic edge enhancement of thin phase samples or spiral-shaped interference fringes for thicker phase samples, which can be used to reconstruct the phase topography from a single on-axis interferogram. If SLMs are used for both illumination control and spatial Fourier filtering, this combination for instance allows for the generalization of the Zernike phase contrast principle. The new SLM-based approach improves the effective resolution and avoids some shortcomings and artifacts of the traditional method. The main advantage of SLMs in microscopy is their flexibility, as one can realize various operation modes in the same setup, without the need for changing any hardware components, simply by electronically switching the phase pattern displayed on the SLMs.”

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Publication: Laser & Photonics Reviews, (subscription required)

Issue/Year/DOI: Laser & Photonics Reviews, Volume 5, Issue 1, pages 81–101, January 2011
DOI: 10.1002/lpor.200900047

Dynamic space shaping of intense ultrashort laser light with blazed-type gratings

Author(s): I. Marienko, V. Denisenko, V Slusar, and M. Soskin

Abstract:

“A beam shaper for dynamic transversal shaping of broadband laser pulses that utilizes a blazed ruled grating and a blazed-type grating simulated on Spatial Light Modulator was demonstrated. The introduced shaper scheme is an extension of 2f-2f scheme [Mariyenko, et al., Opt. Express 13, 7599 (2005)] where the two thin holograms with matched grating constants performed light shaping. The new scheme utilizes the diffraction gratings with different grating constants. Dispersion-free light shaping is achieved by means of the intermediate transversal light beam magnification. The magnification balances the mismatch in the grating constants resulting in total residual angular dispersion compensation. In turn, the magnified beam covers a greater area on the modulator matrix thus reducing the incident light power density by a value equal to square of the magnification factor. It translates to the safe-operation threshold extension of the modulator allowing shaping pulses that are powerful enough to be used in the applications. With a proper components selection, the throughput efficiency of the shaper can be well above 40%. A proper shaper operation was demonstrated with the 140-fs Ti:Sapphire oscillator. Theoretical calculations support the conclusions.”

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Publication: Optics Express, (free download)

Issue/Year/DOI: Optics Express, Vol. 18, Issue 24, pp. 25143-25150 (2010)
doi:10.1364/OE.18.025143

Increasing multimode fiber transmission capacity by mode selective spatial light phase modulation

Author(s): Stepniak, G.; Maksymiuk, L.; Siuzdak, J.;

Abstract:

“We propose spatial light modulation with binary phase filters to increase the transmission bandwidth of multimode fibers. In the experiment more than 300 % of bandwidth enhancement is obtained.”

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Publication: ECOC Proceedings, (subscription required)

Issue/Year/DOI: 36th European Conference and Exhibition on Optical Communication (ECOC), 2010
doi:10.1109/ECOC.2010.5621465

Application of cooled spatial light modulator for high power nanosecond laser micromachining

Author(s): Rainer J. Beck, Jonathan P. Parry, William N. MacPherson, Andrew Waddie, Nick J. Weston, Jonathan D. Shephard, and Duncan P. Hand

Abstract:

“The application of a commercially available spatial light modulator (SLM) to control the spatial intensity distribution of a nanosecond pulsed laser for micromachining is described for the first time. Heat sinking is introduced to increase the average power handling capabilities of the SLM beyond recommended limits by the manufacturer. Complex intensity patterns are generated, using the Inverse Fourier Transform Algorithm, and example laser machining is demonstrated. The SLM enables both complex beam shaping and also beam steering.”

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Publication: Optics Express, (free download)

Issue/Year/DOI: Optics Express, Vol. 18, Issue 16, pp. 17059-17065 (2010)
doi:10.1364/OE.18.017059

A portable laser photostimulation and imaging microscope

Author(s): Volodymyr Nikolenko , Darcy S Peterka, Rafael Yuste

Abstract:

“We describe a compact microscope that uses a spatial light modulator (SLM) to control the excitation laser light. The flexibility of SLMs, which can mimic virtually any optical transfer function, enables the experimenter to create, in software, arbitrary spatio-temporal light patterns, including focusing and beam scanning, simply by calculating the appropriate phase mask. Our prototype, a scan-less device with no moving parts, can be used for laser imaging or photostimulation, supplanting the need for an elaborate optical setup. As a proof of principle, we generate complex excitation patterns on fluorescent samples and also perform functional imaging of neuronal activity in living brain slices.”

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Publication: Journal of Neural Engineering, (free download)

Issue/Year/DOI: J. Neural Eng., Volume 7, Number 4 (2010) 045001
doi: 10.1088/1741-2560/7/4/045001

Optical encryption based on computational ghost imaging

Author(s): Pere Clemente, Vicente Durán, Víctor Torres-Company, Enrique Tajahuerce, Jesús Lancis

Abstract:

“Ghost imaging is an optical technique in which the information of an object is encoded in the correlation of the intensity fluctuations of light. The computational version of this fascinating phenomenon emulates, offline, the optical propagation through the reference arm, enabling 3D visualization of a complex object whose transmitted light is measured by a bucket detector. In this Letter, we show how computational ghost imaging can be used to encrypt and transmit object information to a remote party. Important features, such as key compressibility and vulnerability to eavesdropping, are experimentally analyzed.”

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Publication: Optics Letters (subscription required)

Issue/Year/DOI: Optics Letters, Vol. 35, Issue 14, pp. 2391-2393 (2010)
doi:10.1364/OL.35.002391

Nonlinear response studies and corrections for a liquid crystal spatial light modulator

Author(s): RAVINDER KUMAR BANYAL, B. RAGHAVENDRA PRASAD

Abstract:

“The nonlinear response of light transmission characteristics of a liquid crystal (LC) spatial light modulator (SLM) is studied. The results show that the device exhibits a wide range of variations with different control parameters and input settings. Experiments were performed to obtain intensity modulation that is best described by either power-law or sigmoidal functions. Based on the inverse transformation, an appropriate pre-processing scheme for electrically addressed input gray-scale images, particularly important in several optical processing and imaging applications, is suggested. Further, the necessity to compensate the SLM image nonlinearities in a volume holographic data storage and retrieval system is demonstrated.”

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Publication: PRAMANA Journal of Physics (free download)

Issue/Year/DOI: PRAMANA Journal of Physics, Vol. 74, No. 6, June 2010, pp. 961-971

Materials for an Updatable Holographic 3D Display

Author(s): Cory W. Christenson, Pierre-Alexandre Blanche, Savas Tay, Ram Voorakaranam, Tao Gu, Weiping Lin, Peng Wang, Michiharu Yamamoto, Jayan Thomas, Robert A. Norwood, and Nasser Peyghambarian

Abstract:

“Holography is a powerful technique for providing high-resolution, realistic three-dimensional (3D) images without the need for special eyewear. A material that takes full advantage of the potential of holography, including updatability, has not existed. Here, the first updatable holographic 3D display based on a photorefractive polymer is summarized. The performance characteristics of these materials are measured, and how they relate to the development of additional display enhancements such as pulsed writing, white light viewing, and large viewing angle, are discussed.”

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Publication: Journal of Display Technology – via IEEE Xplore (subscription required)

Issue/Year/DOI: Journal of Display Technology, Issue: 99, pp1-7, (2010)
DOI: 10.1109/JDT.2010.2046620