Method for single-shot fabrication of chiral woodpile photonic structures using phase-controlled interference lithography

Author(s):

Swagato Sarkar, Krishnendu Samanta, and Joby Joseph

Abstract:

“In this report, we propose a large-area, scalable and reconfigurable single-shot
optical fabrication method using phase-controlled interference lithography (PCIL) to realize
submicrometer chiral woodpile photonic structures. This proposed technique involves a 3 + 3
double-cone geometry with beams originated from a computed phase mask displayed on a single
spatial light modulator. Simulation studies show the filtering response of such structures for
linearly polarized plane wave illumination, with structural features tunable through a single
parameter of interference angle. Further, these single chiral woodpile structures show dual
chirality on illumination with both right circularly and left circularly polarized light through
simulation. Experimentally fabricated patterns on photoresist show resemblance to the desired
chiral woodpile structures.”

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Publication: Optics Express

Issue/Year/DOI: Volume 28, Issue 3, pp. 4347-4361
DOI: 10.1364/OE.384987

Velocity measurements with structured light transmitted through a multimode optical fiber using digital optical phase conjugation

Author(s):

Lars Büttner and Martin Thümmler and Jürgen Czarske

Abstract:

“Lensless fiber microendoscopes enable optical diagnostics and therapy with minimal
invasiveness. Because of their small diameters, multimode fibers are ideal candidates, but mode
scrambling hinders the transmission of structured light fields. We present the generation of a
localized fringe system at variable distances from the distal fiber end by exploiting digital optical
phase conjugation. The replayed fringe system was used for quantitative metrology. Velocity
measurements of a microchannel flow in the immediate proximity of the fiber end without the
use of any imaging lenses are shown. Lensless multimode fiber systems are of interest especially
for biomedical imaging and stimulation as well as technical inspection and flow measurements. ”

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Publication: Optics Express

Issue/Year/DOI: Vol. 28, Issue 6, pp. 8064-8075
DOI: 10.1364/OE.386047

Adaptive wavefront interferometry for unknown free-form surfaces

Author(s):

Shuai Xue, Shanyong Chen, Zhanbin Fan and Dede Zhai

Abstract:

“The primary problem of conventional wavefront interferometers is limited dynamic range. Unknown free-form surface figure error with large amplitude or slope is not measurable for too dense or invisible fringes. To troubleshoot this problem, we propose adaptive wavefront interferometry (AWI). AWI utilizes a wavefront sensor-less adaptive optics (AO) subsystem to intelligently speculate and compensate the unknown free-form surface figure error. In this subsystem, adaptive null optics is utilized to iteratively generate adaptive wavefronts to compensate the unknown severe surface figure error. The adaptive null optics is close-loop controlled (i.e., wavefront sensor-less optimization algorithms are utilized to control it by real time monitoring the compensation effects to guarantee convergence of the iteration). Ultimately, invisible fringes turn into resolvable ones, and null test is further realized. To demonstrate the feasibility of AWI, we designed one spatial light modulator (SLM) based AWI modality as an example. The system is based on a commercial interferometer and is easy to establish. No other elements are required besides the SLM. Principle, simulation, and experiments for the SLM based AWI are demonstrated. ”

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Publication: Optics Express

Issue/Year/DOI: Vol. 26, Issue 17, pp. 21910-21928 (2018)
DOI: 10.1364/OE.26.021910

Spectrum and space resolved 4D imaging by coded aperture correlation holography (COACH) with diffractive objective lens

Author(s):

A. Vijayakumar and Joseph Rosen

Abstract:

“In this Letter, we present an advanced optical configuration of coded aperture correlation holography (COACH) with a diffractive objective lens. Four-dimensional imaging of objects at the three spatial dimensions and with an additional spectral dimension is demonstrated. A hologram of three-dimensional objects illuminated by different wavelengths was recorded by the interference of light diffracted from the objects with the light diffracted from the same objects, but through a random-like coded phase mask (CPM). A library of holograms denoted point spread function (PSF) holograms were prerecorded with the same CPM, and under identical conditions, using point objects along different axial locations and for the different illuminating wavelengths. The correlation of the object hologram with the PSF hologram recorded using a particular wavelength, and at a particular axial location, reconstructs only the object corresponding to the particular axial plane and to the specific wavelength. The reconstruction results are compared with regular imaging and with another well-established holographic technique called Fresnel incoherent correlation holography.”

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Publication:  Optics Letters

Issue/Year/DOI: Optics Letters Vol.42, Issue 5, pp. 947-950 (2017)
DOI: 10.1364/OL.42.000947

Closed-loop adaptive optics with a single element for wavefront sensing and correction

Author(s): Raúl Martínez-Cuenca, Vicente Durán, Justo Arines, Jorge Ares, Zbigniew Jaroszewicz, Salvador Bará, Lluís Martínez-León, and Jesús Lancis

Abstract:

“We propose a closed-loop adaptive optical arrangement based on a single spatial light modulator that simultaneously works as a correction unit and as the key element of a wavefront sensor. This is possible by using a liquid crystal on silicon display whose active area is divided into two halves that are respectively programmed for sensing and correction. We analyze the performance of this architecture to implement an adaptive optical system. Results showing a closed-loop operation are reported, as well as a proof of concept for dealing with aberrations comparable to those typically found in human eyes.”

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Publication: Optics Letters, (subscription required)

Issue/Year/DOI: Optics Letters, Vol. 36, Issue 18, pp. 3702-3704 (2011)
doi:10.1364/OL.36.003702

Estimation and Compensation of aberrations in Spatial Light Modulators

Author(s): Augusto Arias and Roman Castaneda

Abstract:

“The spatial light modulator (SLM) Holoeye LC-R720 is based on LCoS (Liquid Crystal on Silicon) technology. Due to the induced curvatures on the silicon plate by the production process, there are static aberrations in the wave-fronts modified by the SLM. In order to calculate the aberrated wave-front we used phase-shifting interferometry, an optimization algorithm for far field propagation, and the geometric characterization of the focal spot along the caustic. Zernike polynomials were used for expanding and comparing the wave-fronts. The aberration compensation was carried out by displaying the conjugated transmittance on the SLM. The complexity of the experimental setup and the requirements of the digital processing of each estimation method were comparatively analyzed.”

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

Issue/Year/DOI: J. Phys.: Conf. Ser., Volume 274, 012060, (2011)
doi:10.1088/1742-6596/274/1/012060

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

Rapid calculation algorithm of Fresnel computer-generated-hologram using look-up table and wavefront-recording plane methods for three-dimensional display

Author(s): Tomoyoshi Shimobaba, Hirotaka Nakayama, Nobuyuki Masuda, and Tomoyoshi Ito

Abstract:

“A rapid calculation method of Fresnel computer-generatedhologram (CGH) using look-up table and wavefront-recording plane (WRP) methods toward three-dimensional (3D) display is presented. The method consists of two steps: the first step is the calculation of a WRP that is placed between a 3D object and a CGH. In the second step, we obtain an amplitude-type or phase-type CGH to execute diffraction calculation from the WRP to the CGH. The first step of the previous WRP method was difficult to calculate in real-time due to the calculation cost. In this paper, in order to obtain greater acceleration, we apply a look-up table method to the first step. In addition, we use a graphics processing unit in the second step. The total computational complexity is dramatically reduced in comparison with conventional CGH calculations. We show optical reconstructions from a 2,048×2,048 phase-type CGH generated by about 3×104 object points over 10 frames per second.”

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Publication: Optics Express, (free download)

Issue/Year/DOI: Optics Express, Vol. 18, Issue 19, pp. 19504-19509 (2010)
doi:10.1364/OE.18.019504

Optical reconstruction of digital holograms recorded at 10.6 μm: route for 3D imaging at long infrared

Author(s): Melania Paturzo, Anna Pelagotti, Andrea Finizio, Lisa Miccio, Massimiliano Locatelli, Andrea Gertrude, Pasquale Poggi, Riccardo Meucci, Pietro Ferraro

Abstract:

“We demonstrate the optical reconstruction in the visible range (0.532μm) of digital holograms recorded at long IR wavelengths (10.6μm) by means of a spatial light modulator. By using an integrated recording-reconstruction system, it is, in fact, feasible to achieve direct imaging of holograms acquired outside the visible range, i.e., in the IR spectrum. By choosing a Fourier recording configuration, the reconstructed image, obtained at about a 20 times shorter wavelength than the acquisition image, exhibits minor aberrations, which do not significantly affect the optical reconstruction. The high NA achievable at a long IR wavelength allows us to image large objects at reasonable distances.”

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Publication: Optics Letters (subscription required)

Issue/Year/DOI: Optics Letters, Vol. 35, Issue 12, pp. 2112-2114 (2010)
doi:10.1364/OL.35.002112

Implementation of a digital optical phase conjugation system and its application to study the robustness of turbidity suppression by phase conjugation

Author(s): Meng Cui, Changhuei Yang

Abstract:

“In this work, we report a novel high capacity (number of degrees of freedom) open loop adaptive optics method, termed digital optical phase conjugation (DOPC), which provides a robust optoelectronic optical phase conjugation (OPC) solution. We showed that our prototype can phase conjugate light fields with ~3.9 x 10−3 degree accuracy over a range of ~3 degrees and can phase conjugate an input field through a relatively thick turbid medium (μsl ~13). Furthermore, we employed this system to show that the reversing of random scattering in turbid media by phase conjugation is surprisingly robust and accommodating of phase errors. An OPC wavefront with significant spatial phase errors (error uniformly distributed from – π/2 to π/2) can nevertheless allow OPC reconstruction through a scattering medium with ~40% of the efficiency achieved with phase error free OPC.”

Link to Publications Page

Publication: Optics Express, (free download)

Issue/Year/DOI: Optics Express, Vol. 18, Issue 4, pp. 3444-3455 (2010)
doi:10.1364/OE.18.003444

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