Holographic display with tilted spatial light modulator

July, 2011

Author(s): Tomasz Kozacki

Abstract:

“In this paper, we analyze a holographic display system utilizing a phase-only spatial light modulator (SLM) based on liquid crystal on silicon (LCoS). An LCoS SLM works in reflection, and, in some applications, it is convenient to use with an inclined illumination. Even with a highly inclined illumination, the holographic display is capable of good-quality image generation. We show that the key to obtain high-quality reconstructions is the tilt-dependent calibration and algorithms. Typically, an LCoS SLM is illuminated with a plane wave with normal wave vector. We use inclined illumination, which requires development of new algorithms and display characterization. In this paper we introduce two algorithms. The first one is designed to process a digital hologram captured in CCD normal configuration, so it can be displayed in SLM tilted geometry, while the second one is capable of synthetic hologram generation for tilted SLM configuration. The inclined geometry asymmetrically changes the field of view of a holographic display. The presented theoretical analysis of the aliasing effect provides a formula for the field of view as a function of SLM tilt. The incidence angle affects SLM performance. Both elements of SLM calibration, i.e., pixel phase response and wavefront aberrations, strongly depend on SLM tilt angle. The effect is discussed in this paper. All of the discussions are accompanied with experimental results.”

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Publication: Applied Optics, (subscription required)

Issue/Year/DOI: Applied Optics, Vol. 50, Issue 20, pp. 3579-3588 (2011)
doi:10.1364/AO.50.003579


A high speed wavefront determination method based on spatial frequency modulations for focusing light through random scattering media

February, 2011

Author(s): Meng Cui

Abstract:

“A large number of degrees of freedom are required to produce a high quality focus through random scattering media. Previous demonstrations based on spatial phase modulations suffer from either a slow speed or a small number of degrees of freedom. In this work, a high speed wavefront determination technique based on spatial frequency domain wavefront modulations is proposed and experimentally demonstrated, which is capable of providing both a high operation speed and a large number of degrees of freedom. The technique was employed to focus light through a strongly scattering medium and the entire wavefront was determined in 400 milliseconds, ~three orders of magnitude faster than the previous report.”

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Publication: Optics Express, (free download)

Issue/Year/DOI: Optics Express, Vol. 19, Issue 4, pp. 2989-2995 (2011)
doi:10.1364/OE.19.002989


Dynamic generation of Debye diffraction-limited multifocal arrays for direct laser printing nanofabrication

January, 2011

Author(s): Han Lin, Baohua Jia, and Min Gu

Abstract:

“We propose a Debye-theory-based iterative method to produce accurate phase patterns for generating highly uniform diffraction-limited multifocal arrays with a high-NA objective. It is shown that by using the Debye method, the uniformity of the diffraction-limited focal arrays can reach 99%, owing to the critical consideration of the depolarization effect associated with high-NA objectives. The generated phase patterns are implemented in fast dynamic laser printing nanofabrication for the generation of individually controlled high-quality microvoid arrays in a solid polymer material by a single exposure of a femtosecond laser beam. As a result of the high-quality multifocal arrays, functional three-dimensional photonic crystals possessing multiple stopgaps with suppression up to 80% in transmission spectra are demonstrated.”

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Publication: Optics Letters, (subscription required)

Issue/Year/DOI: Optics Letters, Vol. 36, Issue 3, pp. 406-408 (2011)
doi:10.1364/OL.36.000406


Frequency bandwidth of light focused through turbid media

January, 2011

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


A SAR multilook optronic processor for operational Earth monitoring applications

September, 2010

Author(s): Linda Marchese, Pascal Bourqui, Sandra Turgeon, Michel Doucet, Carl Vachon, François Châteauneuf, Alain Bergeron, Bernd Harnisch and Martin Suess.

Abstract:

“Synthetic Aperture Radar (SAR) is the only remote sensing technology that can provide high resolution images in adverse weather conditions and in day or night times. It is thus is a powerful tool for Earth monitoring. Certain applications, such as disaster relief, military reconnaissance and ice-flow and ship monitoring require a continuous flow of high-resolution images covering large areas; however, given the large amount of complex data generated and system limitations of data bandwidth and processing speed, not all the requirements can be met at the same time. In addition, multiple user requests are often submitted to the SAR system platform, and not all can be addressed, again due to limitations of area coverage. Increasing the speed of SAR processors and processing on-board are two ways to improve the SAR data throughput and therefore to meet the operational needs of all users. This paper discusses an optronic SAR processor capable of rapidly processing full-scene multi-looked images. Details of the processor design and image results are discussed. Estimations for speed and image throughput are provided, all presented in the context of the requirements for operational service of the various applications.”

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Publication: SPIE Proceedings, (subscription required)

Issue/Year/DOI: Proc. SPIE, Volume 7829, 782904 (2010)
doi:10.1117/12.866986


Imaging through turbid layers by scanning the phase conjugated second harmonic radiation from a nanoparticle

September, 2010

Author(s): Chia-Lung Hsieh, Ye Pu, Rachel Grange, Grégoire Laporte, Demetri Psaltis

Abstract:

“We demonstrate imaging through a turbid layer by using digital phase conjugation of the second harmonic field radiated from a beacon nanoparticle. We show that the phase-conjugated focus can be displaced from its initial position by illuminating the same region of the turbid layer with an angular offset. An image is obtained by scanning the phase-conjugated focus through the turbid layer in a region around the nanoparticle. We obtain a clear image of the target by measuring the light transmitted through it when scanning the focused beam.”

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Publication: Optics Express, (free download)

Issue/Year/DOI: Optics Express, Vol. 18, Issue 20, pp. 20723-20731 (2010)
doi:10.1364/OE.18.020723


Reconfigurable all-diffractive optical filters using phase-only spatial light modulators

July, 2010

Author(s): Gladys Mínguez-Vega, V. R. Supradeepa, Omel Mendoza-Yero, Andrew M. Weiner

Abstract:

“We demonstrate a reconfigurable optical filter implemented using a phase-only two-dimensional liquid-crystal-on-silicon spatial light modulator. To achieve this we utilize two different approaches leading to two different configurations in the modulator. The first one, based on a spatially patterned diffractive lens, permits us to obtain the desired spectrum along the optical axis and, in the second one, which is based on a generalized spectrometer, the desired spectrum is found outside of the optical axis. Experimental results show good agreement with the theory and indicate the validity of this technique.”

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Publication: Optics Letters (subscription required)

Issue/Year/DOI: Optics Letters, Vol. 35, Issue 14, pp. 2406-2408 (2010)
doi:10.1364/OL.35.002406


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

June, 2010

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


Digital phase conjugation of second harmonic radiation emitted by nanoparticles in turbid media

May, 2010

Author(s): Chia-Lung Hsieh, Ye Pu, Rachel Grange, and Demetri Psaltis

Abstract:

“We demonstrate focusing coherent light on a nanoparticle through turbid media based on digital optical phase conjugation of second harmonic generation (SHG) field from the nanoparticle. A SHG active nanoparticle inside a turbid medium was excited at the fundamental frequency and emitted SHG field as a point source. The SHG emission was scattered by the turbid medium, and the scattered field was recorded by off-axis digital holography. A phase-conjugated beam was then generated by using a phase-only spatial light modulator and sent back through the turbid medium, which formed a nearly ideal focus on the nanoparticle.”

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Publication: Optics Express, (free download)

Issue/Year/DOI: Optics Express, Vol. 18, Issue 12, pp. 12283-12290 (2010)
doi:10.1364/OE.18.012283


PHASE MEASUREMENT OF OPTICAL WAVEFRONT BY AN SLM DIFFERENTIATION FILTER

September, 2009

Author(s): Hideo Furuhashi, Javier Valle Mayorga, Yoshiyuki Uchida, Akihiro Kono

Abstract:

“A system is proposed that employs a spatial light modulator as a differentiation filter to measure the phase of an optical wavefront. The pattern, position and orientation of the filter can be controlled electrically. This system measures the phase derivative of a wavefront that passes through a transparent phase object. The 3D shape of the object can be calculated by integrating the phase derivative.”

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Publication: XIX IMEKO World Congress, (free download)

Issue/Year/DOI: XIX IMEKO World Congress, Fundamental and Applied Metrology, September 6−11, 2009