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Discrete time-stretch LiDAR (Conference Presentation)
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Paper Abstract

Photonic time-stretch has established world’s fastest real-time spectrometers and cameras with applications in biological cell screening, tomography, microfluidics, velocimetry and vibrometry. In time-stretch imaging, the target’s spatial information is encoded in the spectrum of the broadband laser pulses, which is stretched in time and then detected by a single-pixel detector and digitized by a real-time ADC, and processed by a CPU or a dedicated FPGA or GPU. In time-of-flight LiDAR measurement, the maximum detectable distance scales with the temporal duration of the chirped illumination source. The bearing angle is proportional to the bandwidth of the source. In order to have a large detection angle and depth, a large chirp-bandwidth product is required. Various methods have been proposed to generate a chirped output to realize time-stretch, including single mode fibers, dispersion compensating fibers, chirped Bragg grating, and chromo-modal dispersion (CMD). But none of those methods provide the chirped source with a large time-bandwidth product. Moreover, the chirp profile and the operating wavelength can be changed with minimum freedom in those methods. In this study, we demonstrate the discrete time-stretch method that can generate the giant time-bandwidth product with arbitrary nonlinear chirp at operating wavelength from the visible to the infrared. A chirped pulse train with chirp time-bandwidth product at the order of 106 is easily feasible, rendering time-of-flight imaging of long-ranging distance and large bearing angle possible. We show its application in spectral-temporal LIDAR with the foveated vision at MHz refresh rate.

Paper Details

Date Published: 4 March 2019
Proc. SPIE 10908, Frontiers in Ultrafast Optics: Biomedical, Scientific, and Industrial Applications XIX, 109080I (4 March 2019); doi: 10.1117/12.2510843
Show Author Affiliations
Yunshan Jiang, Univ. of California, Los Angeles (United States)
Sebastian Karpf, Univ. of California, Los Angeles (United States)
Bahram Jalali, Univ. of California, Los Angeles (United States)

Published in SPIE Proceedings Vol. 10908:
Frontiers in Ultrafast Optics: Biomedical, Scientific, and Industrial Applications XIX
Peter R. Herman; Michel Meunier; Roberto Osellame, Editor(s)

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