Coherent two-photon LIDAR with incoherent light

Chung Hyun Lee, Yosep Kim, Dong Gil Im, U. Shin Kim, Vincenzo Tamma, Yoon Ho Kim

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Abstract

Coherent light detection and ranging (LIDAR) offers exceptional sensitivity and precision in measuring the distance of remote objects by employing first-order interference. However, the ranging capability of coherent LIDAR is principally constrained by the coherence time of the light source determined by the spectral bandwidth. Here, we introduce coherent two-photon LIDAR, which eliminates the range limitation of coherent LIDAR due to the coherence time. Our scheme capitalizes on the counterintuitive phenomenon of two-photon interference of thermal light, in which the second-order interference fringe remains impervious to the short coherence time of the light source determined by the spectral bandwidth. By combining this feature with transverse two-photon interference of thermal light, we demonstrate distance ranging beyond the coherence time without relying on time-domain interference fringes. Moreover, we show that our coherent two-photon LIDAR scheme is robust to turbulence and ambient noise. This work opens up novel applications of two-photon correlation in classical light.

Original languageEnglish
Article number223602
Number of pages6
JournalPhysical Review Letters
Volume131
Issue number22
DOIs
Publication statusPublished - 28 Nov 2023

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