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

The Applications and Technology of Phase-Only Liquid Crystal on Silicon Devices

Author(s): Collings, N.; Davey, T.; Christmas, J.; Chu, D.; Crossland, B.

Abstract:

“An introduction to the technology of liquid crystal on silicon (LCOS) devices leads on to a discussion of the application areas which have been and are being opened up by the development of phase-only devices.”

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Publication: Journal of Display Technology
Issue/Year: Journal of Display Technology, Vol. 7, Issue 3, pp. 112-119 (2010)
DOI: 10.1109/JDT.2010.2049337

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

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

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

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

Full 3D translational and rotational optical control of multiple rod-shaped bacteria

Author(s): Florian Hörner, Mike Woerdemann, Stephanie Müller, Berenike Maier, Cornelia Denz

Abstract:

“The class of rod-shaped bacteria is an important example of non-spherical objects where defined alignment is desired for the observation of intracellular processes or studies of the flagella. However, all available methods for orientational control of rod-shaped bacteria are either limited with respect to the accessible rotational axes or feasible angles or restricted to one single bacterium. In this paper we demonstrate a scheme to orientate rod-shaped bacteria with holographic optical tweezers (HOT) in any direction. While these bacteria have a strong preference to align along the direction of the incident laser beam, our scheme provides for the first time full rotational control of multiple bacteria with respect to any arbitrary axis. In combination with the translational control HOT inherently provide, this enables full control of all three translational and the two important rotational degrees of freedom of multiple rod-shaped bacteria and allows one to arrange them in any desired configuration.”

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Publication: Journal of Biophotonics
Issue/Year: Journal of Biophotonics, Volume 3, Issue 7, pages 468–475, July 2010
DOI: 10.1002/jbio.201000033