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

Rapid phase calibration of a spatial light modulator using novel phase masks and optimization of its efficiency using an iterative algorithm

Author(s):

Amar Deo Chandra and Ayan Banerjee

Abstract:

“We develop an improved phase calibration method of a reflective SLM using interferometry by employing novel phase masks. In the process, we definitively determine the actual maximum phase throw of our SLM which provides a recipe for users to verify supplier specifications. We generate optimised phase masks by using Iterative Fourier Transform Algorithm (IFTA) and compare their performance with global linear corrections in the look-up table (LUT) and find that the former perform with around 20% better efficiency. Besides obtaining an array of 1D/2D spots having high uniformity (90%) using IFTA, our result exemplifies the use of iterative algorithms for improving efficiency of phase limited SLMs. Finally, our improved phase calibration method enables threefold faster phase measurements, and to the best of our knowledge, is the first endeavour directed towards enabling rapid phase characterisation of an SLM using interferometric measurements. We believe that it can have very useful applications in settings which may require fast phase calibrations as well as for real-time, multi-wavelength spectroscopic applications.”

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Publication: Journal of Modern Optics

Issue/Year/DOI: Volume 67- Issue 7
DOI: 10.1080/09500340.2020.1760954

Flexible measurement of high-order optical orbital angular momentum with a variable cylindrical lens pair

Author(s):

Jianneng Lu, Chongyang Cao, Zhuqing Zhu and Bing Gu

Abstract:

“We present a method to measure the high-order optical orbital angular momentum (OAM) with a variable cylindrical lens pair. The optical system consists of two cylindrical lenses with the opposite focal length. It produces a rotating position—spatial frequency transformation of phase modulation by changing the angle between the two cylindrical lenses. With this feature, the method can flexibly measure the OAM states of the vortex beams with different beam waists. The OAM states are determined by the number and direction of dark stripes of the diffraction pattern. The measurements of the topological charge and the radial index of Laguerre–Gaussian mode are demonstrated. As a compact high-order OAM measuring device, the variable cylindrical lens pair may find potential applications in optical communication.
This work was funded by the National Natural Science Foundation of China (Nos. 11774055 and 61875093), the Natural Science Foundation of Jiangsu Province of China (No. BK20181384) and the Natural Science Foundation of Tianjin of China (No. 19JCYBJC16500).”

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Publication: Applied Physics Letters

Issue/Year/DOI: Appl. Phys. Lett. Volume:116 (2020)
DOI: 10.1063/5.0002756