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Keywords = rotational-shear interferometer

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11 pages, 3555 KB  
Article
Control of the Optical Wavefront in Phase and Amplitude by a Single LC-SLM in a Stellar Coronagraph Aiming for Direct Exoplanet Imaging
by Andrey Yudaev, Alla Venkstern, Irina Shulgina, Alexander Kiselev, Alexander Tavrov and Oleg Korablev
Photonics 2024, 11(4), 300; https://doi.org/10.3390/photonics11040300 - 26 Mar 2024
Viewed by 1774
Abstract
This article presents a novel approach to actively compensate wavefront errors in both phase and amplitude using a Liquid Crystal Spatial Light Modulator (LC-SLM) for direct exoplanet imaging. This method involves controlling the wavefront to address challenges posed by stellar coronagraphy. Experimental results [...] Read more.
This article presents a novel approach to actively compensate wavefront errors in both phase and amplitude using a Liquid Crystal Spatial Light Modulator (LC-SLM) for direct exoplanet imaging. This method involves controlling the wavefront to address challenges posed by stellar coronagraphy. Experimental results demonstrate successful wavefront error compensation in both phase and amplitude components. This technique shows promise for direct exoplanet imaging and may be applied onboard orbital telescopes in the future. Full article
(This article belongs to the Special Issue Optical Systems for Astronomy)
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10 pages, 3011 KB  
Communication
Enhanced Readout from Spatial Interference Fringes in a Point-Source Cold Atom Inertial Sensor
by Jing Wang, Junze Tong, Wenbin Xie, Ziqian Wang, Yafei Feng and Xiaolong Wang
Sensors 2023, 23(11), 5071; https://doi.org/10.3390/s23115071 - 25 May 2023
Cited by 3 | Viewed by 2161
Abstract
When the initial size of an atom cloud in a cold atom interferometer is negligible compared to its size after free expansion, the interferometer is approximated to a point-source interferometer and is sensitive to rotational movements by introducing an additional phase shear in [...] Read more.
When the initial size of an atom cloud in a cold atom interferometer is negligible compared to its size after free expansion, the interferometer is approximated to a point-source interferometer and is sensitive to rotational movements by introducing an additional phase shear in the interference sequence. This sensitivity on rotation enables a vertical atom-fountain interferometer to measure angular velocity in addition to gravitational acceleration, which it is conventionally used to measure. The accuracy and precision of the angular velocity measurement depends on proper extraction of frequency and phase from spatial interference patterns detected via the imaging of the atom cloud, which is usually affected by various systematic biases and noise. To improve the measurement, a pre-fitting process based on principal component analysis is applied to the recorded raw images. The contrast of interference patterns are enhanced by 7–12 dB when the processing is present, which leads to an enhancement in the precision of angular velocity measurements from 6.3 μrad/s to 3.3 μrad/s. This technique is applicable in various instruments that involve precise extraction of frequency and phase from a spatial interference pattern. Full article
(This article belongs to the Special Issue Quantum Sensors and Quantum Sensing)
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20 pages, 5969 KB  
Article
Wavefront Sensing by a Common-Path Interferometer for Wavefront Correction in Phase and Amplitude by a Liquid Crystal Spatial Light Modulator Aiming the Exoplanet Direct Imaging
by Andrey Yudaev, Alexander Kiselev, Inna Shashkova, Alexander Tavrov, Alexander Lipatov and Oleg Korablev
Photonics 2023, 10(3), 320; https://doi.org/10.3390/photonics10030320 - 16 Mar 2023
Cited by 1 | Viewed by 2806
Abstract
We implemented the common-path achromatic interfero-coronagraph both for the wavefront sensing and the on-axis image component suppression, aiming for the stellar coronagraphy. A common-path achromatic interfero-coronagraph has its optical scheme based on a nulling rotational-shear interferometer. The angle of rotational shear can be [...] Read more.
We implemented the common-path achromatic interfero-coronagraph both for the wavefront sensing and the on-axis image component suppression, aiming for the stellar coronagraphy. A common-path achromatic interfero-coronagraph has its optical scheme based on a nulling rotational-shear interferometer. The angle of rotational shear can be chosen at a small angular extent of about 10 deg. Such a small angular shear maintains the coronagraphic contrast degradation known as the stellar leakage effect, caused by a finite stellar size. We study the phase and amplitude wavefront control by a liquid crystal spatial light modulator of reflection type which is used as the pixilated active adaptive optics unit. Therefore, adaptive optics perform a wavefront-correcting input toward a stellar interfero-coronagraph aiming at the direct exoplanet imaging. Presented here are both the numeric evaluations and the lab experiment stand to prove the declared functionality output. Full article
(This article belongs to the Special Issue Optical Systems for Astronomy)
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12 pages, 1830 KB  
Article
Rotational Shearing Interferometer in Detection of the Super-Earth Exoplanets
by Marija Strojnik
Appl. Sci. 2022, 12(6), 2840; https://doi.org/10.3390/app12062840 - 10 Mar 2022
Cited by 4 | Viewed by 2474
Abstract
The astronomers and the general population are fascinated with the problem of exoplanet detection. By far the largest number of detected planets are the so-called Super Earths, relatively cold planets orbiting a large, red giant star, with diameters up to 1 AU, most [...] Read more.
The astronomers and the general population are fascinated with the problem of exoplanet detection. By far the largest number of detected planets are the so-called Super Earths, relatively cold planets orbiting a large, red giant star, with diameters up to 1 AU, most of them at about one hundred light-year distance from us. A rotational shearing interferometer (RSI) was proposed for exoplanet detection. Here the detection capabilities of the RSI are expanded to include the case when the interferometer is not precisely aligned on the star. The theoretical analysis is applied to the case of a Super Earth with the red giant star, displaced from the origin to the Mercury, Earth, and the Martian orbit. For errors in alignment up to the Mercury orbit, the red giant star generates a slanted radiance pattern that may be eliminated using information processing. For larger distances, analysis in the Fourier domain is feasible. Full article
(This article belongs to the Special Issue Progress in 3OM: Opto-Mechatronics, Opto-Mechanics, and Optical Metrology)
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10 pages, 7522 KB  
Article
Rotational-Shearing-Interferometer Response for a Star-Planet System without Star Cancellation
by Beethoven Bravo-Medina, Marija Strojnik, Azael Mora-Nuñez and Héctor Santiago-Hernández
Appl. Sci. 2021, 11(8), 3322; https://doi.org/10.3390/app11083322 - 7 Apr 2021
Cited by 6 | Viewed by 2126
Abstract
The Rotational Shearing Interforometer has been proposed for direct detection of extra-solar planets. This interferometer cancels the star radiation using destructive interference. However, the resulting signal is too small (few photons/s for each m2). We propose a novel method to enhance [...] Read more.
The Rotational Shearing Interforometer has been proposed for direct detection of extra-solar planets. This interferometer cancels the star radiation using destructive interference. However, the resulting signal is too small (few photons/s for each m2). We propose a novel method to enhance the signal magnitude by means of the star–planet interference when the star radiation is not cancelled. We use interferograms computationally simulated to confirm the viability of the technique. Full article
(This article belongs to the Special Issue Image Simulation in Remote Sensing)
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