Adaptive optics via pupil segmentation for high-resolution imaging in biological tissues

Author(s): Na Ji, Daniel E Milkie, Eric Betzig

Abstract:

“Biological specimens are rife with optical inhomogeneities that seriously degrade imaging performance under all but the most ideal conditions. Measuring and then correcting for these inhomogeneities is the province of adaptive optics. Here we introduce an approach to adaptive optics in microscopy wherein the rear pupil of an objective lens is segmented into subregions, and light is directed individually to each subregion to measure, by image shift, the deflection faced by each group of rays as they emerge from the objective and travel through the specimen toward the focus. Applying our method to two-photon microscopy, we could recover near-diffraction–limited performance from a variety of biological and nonbiological samples exhibiting aberrations large or small and smoothly varying or abruptly changing. In particular, results from fixed mouse cortical slices illustrate our ability to improve signal and resolution to depths of 400 μm.”

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Publication: Nature Methods, (subscription required)

Issue/Year/DOI: Nature Methods 7, 141 – 147 (2009)
doi:10.1038/nmeth.1411

Digital Holographic Capture and Optoelectronic Reconstruction for 3D Displays

Author(s): Damien P. Kelly, David S. Monaghan, Nitesh Pandey, Tomasz Kozacki, Aneta Michałkiewicz, Grzegorz Finke, Bryan M. Hennelly, Malgorzata Kujawinska

Abstract:

“The application of digital holography as a viable solution to 3D capture and display technology is examined. A review of the current state of the field is presented in which some of the major challenges involved in a digital holographic solution are highlighted. These challenges include (i) the removal of the DC and conjugate image terms, which are features of the holographic recording process, (ii) the reduction of speckle noise, a characteristic of a coherent imaging process, (iii) increasing the angular range of perspective of digital holograms (iv) and replaying captured and/or processed digital holograms using spatial light modulators. Each of these challenges are examined theoretically and several solutions are put forward. Experimental results are presented that demonstrate the validity of the theoretical solutions.”

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Publication: International Journal of Digital Multimedia Broadcasting, (free download)

Issue/Year/DOI: International Journal of Digital Multimedia Broadcasting, Volume 2010 (2010), Article ID 759323
doi:10.1155/2010/759323

Generating superpositions of higher–order Bessel beams

Author(s): Ruslan Vasilyeu, Angela Dudley, Nikolai Khilo, Andrew Forbes

Abstract:

“We report the first experimental generation of the superposition of higher-order Bessel beams, by means of a spatial light modulator (SLM) and a ring slit aperture. We present illuminating a ring slit aperture with light which has an azimuthal phase dependence, such that the field produced is a superposition of two or more higher-order Bessel beams. The experimentally produced fields are in good agreement with those calculated theoretically. The significance of these fields is that even though one is able to generate fields which carry zero orbital angular momentum, a rotation in the field’s intensity profile as it propagates is observed.”

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Publication: Optics Express (free download)

Issue/Year/DOI: Optics Express, Vol. 17, Issue 26, pp. 23389-23395 (2009)
doi:10.1364/OE.17.023389

Rotating single atoms in a ring lattice generated by a spatial light modulator

Author(s): Xiaodong He, Peng Xu, Jin Wang, and Mingsheng Zhan

Abstract:

“We demonstrated trapping single neutral Rb atoms in micro traps of an optical ring lattice formed by superposing the ±l components of the Laguerre-Gaussian mode, and generated by reflecting a single laser beam from a computer controlled spatial light modulator. A single atom in one trap or two atoms with one each in two traps were identified by observing the fluorescence. The trap array loaded with single atoms was rotated by dynamically displaying the hologram animation movie on the modulator. The modulation period in the fluorescence indicates the rotation of one or two single atoms in the lattice.”

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Publication: Optics Express, (free download)

Issue/Year/DOI: Optics Express, Vol. 17, Issue 23, pp. 21007-21014 (2009)
doi:10.1364/OE.17.021007

Optical mirror trap with a large field of view

Author(s): Maximilian Pitzek, Ruth Steiger, Gregor Thalhammer, Stefan Bernet, and Monika Ritsch-Marte

Abstract:

“Holographic optical tweezers typically require microscope objectives with high numerical aperture and thus usually suffer from the disadvantage of a small field of view and a small working distance. We experimentally investigate an optical mirror trap that is created after reflection of two holographically shaped collinear beams on a mirror. This approach combines a large field of view and a large working distance with the possibility to manipulate particles in a large size range, since it allows to use a microscope objective with a numerical aperture as low as 0.2. In this work we demonstrate robust optical three-dimensional trapping in a range of 1mm x 1mm x 2mm with particle sizes ranging from 1.4 μm up to 45 μm. The use of spatial light modulator based holographic methods to create the trapping beams allows to simultaneously trap many beads in complex, dynamic configurations. We present measurements that characterize the mirror traps in terms of trap stiffness, maximum trapping force and capture range.”

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Publication: Optics Express, (free download)

Issue/Year/DOI: Optics Express, Vol. 17, Issue 22, pp. 19414-19423 (2009)
doi:10.1364/OE.17.019414

Compact Optical Tweezers Based on SLM for Real-Time Optical Trapping and Manipulation

Author(s): Martin Nyvlt, Marek Skeren

Abstract:

“We report a compact holographic optical tweezers based on an LCoS SLM. Optical traps are generated by diffraction of light on the Fresnel-type hologram generated by a fast parallel algorithm that enables real-time 3-D manipulation.”

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Publication: Conference Paper Frontiers in Optics (FiO) – via Optics InfoBase, (subscription required)

Issue/Year/DOI: onference Paper Frontiers in Optics (FiO), October 11, 2009

Generating Superpositions of Higher Order Bessel Beams

Author(s): Ruslan Vasilyeu, Angela Dudley, N. Khilo, and Andrew Forbes

Abstract:

“An experimental setup to generate a superposition of higher-order Bessel beams by means of a spatial light modulator and ring aperture is presented. The experimentally produced fields are in good agreement with those calculated theoretically.”

Link to Publications Page

Publication: Conference Paper: Frontiers in Optics (FiO) Oct 11, 2009, (subscription required)

Speed-up of hologram generation using ClearSpeed Accelerator board

Author(s): Noriyuki Tanabe, Yasuyuki Ichihashi, Hirotaka Nakayama, Nobuyuki Masuda and Tomoyoshi Ito

Abstract:

“We have sped up the calculation of a computer-generated hologram by parallel computing using ClearSpeed Advance Dual CSX600 PCI-X Accelerator Board by ClearSpeed Technology plc. By using two boards in parallel, our system was able to perform the calculation 50 times as fast as a personal computer.”

Link to Publications Page

Publication: Computer Physics Communications – via ScienceDirect.com (subscription required)

Issue/Year/DOI: Computer Physics Communications, Volume 180, Issue 10, October 2009, Pages 1870-1873
doi:10.1016/j.cpc.2009.06.001

Spatial light modulator as a reconfigurable intracavity dispersive element for tunable lasers

Author(s): Lin Dong, Sergei Popov, Sergey Sergeyev and Ari T. Friberg

Abstract:

“An improved approach for narrow-band wavelength selection in tunable lasers is described. To provide the tunability, a reconfigurable diffractive optical element (DOE) based on a programmable spatial light modulator (PSLM) is applied. With a proper choice of the phase transfer function of the PSLM, the device can be used as a dispersive intra-cavity component for precise tuning within the lasing spectral band of a solid-state dye laser. The suggested design allows avoiding the mechanical movement of any cavity components. The tunability performance and simulation are demonstrated using the Fourier optics method. ”

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Publication: Central European Journal of Physics, (subscription required)

Issue/Year/DOI: Central European Journal of Physics, Volume 8, Number 2, 228-234, (2009)
DOI: 10.2478/s11534-009-0151-4

Superhydrophobic surface structures in thermoplastic polymers by interference lithography and thermal imprinting

Author(s): Christian W.J. Berendsen, Marek Škereň, David Najdek and František Cerný

Abstract:

“We present a method to produce superhydrophobic surfaces in thermoplastic polymer substrates. The method involves the creation of a nickel stamp using a customized laser interference lithography technique and electroplating processes. This stamp is used to emboss sub-micrometer periodic structures into the thermoplastic. The modified surface is coated with a hydrophobic plasma-polymerized hexafluoropropene layer. Surfaces with different periodicity and relief depth were created. On the surface with the highest aspect ratio, advancing water contact angles of 167° were measured with a water contact angle hysteresis of below 5°.”

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Publication: Applied Surface Science – ScienceDirect.com (subscription required)

Issue/Year/DOI: Applied Surface Science, Volume 255, Issue 23, 15 September 2009, Pages 9305-9310
doi:10.1016/j.apsusc.2009.07.001

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