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Optical stellar interferometers have demonstrated milli-arcsecond resolution with few apertures spaced hundreds of meters apart. To obtain rich direct images, many apertures will be needed, for a better sampling of the incoming wavefront.…

Instrumentation and Methods for Astrophysics · Physics 2014-09-17 Arun Surya , Swapan K. Saha , Antoine Labeyrie

Flexible fiber-optic endoscopes provide a minimally-invasive solution for imaging at depths beyond the reach of conventional microscopes. Current endoscopes require focusing and/or scanning mechanisms at the distal end, which limit…

In fiber-based spectroscopy within telescopes, a prevailing limitation has been the necessity to align the fiber diameter with the telescope's seeing conditions, often characterized by the Full Width at Half Maximum of the point spread…

Instrumentation and Methods for Astrophysics · Physics 2024-06-25 Nitish Singh , S. Sriram , Bharat Kumar Yerra , Prasanna G. Deshmukh

We experimentally demonstrate an all-fiber spectrometer consisting of a photonic bandgap fiber bundle and a black and white CCD camera. Photonic crystal fibers used in this work are the large solid core all-plastic Bragg fibers designed for…

Optics · Physics 2015-05-18 Qu Hang , Bora Ung , Imran Syed , Ning Guo , Maksim Skorobogatiy

This work is concerned with optical imaging in strongly diffusive environments. We consider a typical setting in optical coherence tomography where a sample is probed by a collection of wavefields produced by a laser and propagating through…

Optics · Physics 2024-12-10 Randy Bartels , Olivier Pinaud , Maxine Varughese

A flexible multimode fiber is an exceptionally efficient tool for in vivo deep tissue imaging. Recent advances in compressive multimode fiber sensing allow for imaging with sub-diffraction spatial resolution and sub-Nyquist speed. At…

Optics · Physics 2024-07-17 Zhouping Lyu , Shih-Te Hung , Carlas S. Smith , Lyubov V. Amitonova

We present an efficient approach and principle experiment for compressive sensing (CS) fluorescence spectral imaging. According to the dimension-reduced effect of CS, the spectral and spatial information was simultaneously obtained by using…

Instrumentation and Detectors · Physics 2017-07-07 Chao Wang , Xue-Feng Liu , Wen-Kai Yu , Xu-Ri Yao , Fu Zheng , Qian Dong , Ruo-Ming Lan , Guang-Jie Zhai , Qing Zhao

Snapshot spectral imaging is rapidly gaining interest for remote sensing applications. Acquiring spatial and spectral data within one image promotes fast measurement times, and reduces the need for stabilized scanning imaging systems. Many…

Image and Video Processing · Electrical Eng. & Systems 2018-12-05 Rebecca French , Sylvain Gigan , Otto L. Muskens

Conventional ground-based optical telescopes, even those with large apertures, primarily observe stars, close binaries, and multiple systems as unresolved point sources through photometric measurements. Spectroscopy can identify multiple…

Instrumentation and Methods for Astrophysics · Physics 2025-12-10 Km Nitu Rai , Neelam Panwar , Jeewan C Pandey , T S Kumar , Subrata Sarangi , Prasenjit Saha

We demonstrate in vivo endoscopic optical coherence tomography (OCT) imaging in the forward direction using a flexible fiber bundle. In comparison to current conventional forward looking probe schemes, our approach simplifies the endoscope…

Laser speckle, the granular intensity pattern arising from random optical interference, provides a high-dimensional encoding of spectral information that can be exploited for precision metrology. Speckle-based spectrometers have advanced…

Speckle is the spatial fluctuation of irradiance seen when coherent light is reflected from a rough surface. It is due to light reflected from the surface's many nooks and crannies accumulating vastly-discrepant time delays, spanning much…

Optics · Physics 2020-08-26 Justin Dove , Jeffrey H. Shapiro

Despite advances in low-light level detection, single-photon methods such as photon correlation have rarely been used in the context of imaging. The few demonstrations, for example of sub-diffraction limited imaging utilizing quantum…

Optics · Physics 2017-03-14 Yonatan Israel , Ron Tenne , Dan Oron , Yaron Silberberg

The fields of view of Extremely Large Telescopes will contain vast numbers of spatial sampling elements (spaxels) as their Adaptive Optics systems approach the diffraction limit over wide fields. Since this will exceed the detection…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 G. J. Murray , J. R. Allington-Smith

Conventional lens-based imaging techniques have long been limited to capturing only the intensity distribution of objects, resulting in the loss of other crucial dimensions such as spectral data. Here, we report a spectral lens that…

Residual speckles due to aberrations arising from optical errors after the split between the wavefront sensor and the science camera path are the most significant barriers to imaging extrasolar planets. While speckles can be suppressed…

Instrumentation and Methods for Astrophysics · Physics 2016-10-12 Michael Bottom , J. Kent Wallace , Randall D. Bartos , J. Chris Shelton , Eugene Serabyn

The speckle imaging is a photographic technique that resolves objects viewed through severely distorted media. The results are insensitive to the errors caused by apparent size of the isoplanatic patch and the telescope aberrations. In this…

Astrophysics · Physics 2007-05-23 S K Saha

Recovering the wavelength from disordered speckle patterns has become an exciting prospect as a wavelength measurement method due to its high resolution and simple design. In previous studies, panel cameras have been used to detect the…

Instrumentation and Detectors · Physics 2023-08-14 Tianliang Wang , Yi Li , Xinyu Gao , Jinchao Tao , Xu Wang , Qin Liang , Yanqing Qiu , Bangning Mao , Yanlong Meng

We present a feasibility study exploring the implementation of optical interferometry and speckle techniques with the 1.3-m Devasthal Fast Optical Telescope (DFOT) at ARIES, which is currently dedicated to photometric observations. Using…

Instrumentation and Methods for Astrophysics · Physics 2026-02-16 Km Nitu Rai , Arjun Dawn , Neelam Panwar , Jeewan C Pandey , Subrata Sarangi , Prasenjit Saha

We describe a new concept for a MEMS-based active spatial filter for astronomical spectroscopy. The goal of this device is to allow the use of a diffraction-limited spectrometer on a seeing limited observation at improved throughput over a…

Astrophysics · Physics 2009-11-11 A. I. Sheinis , L. Nigra , M. Q. Kuhlen
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