High energy LiDAR source for long distance, high resolution range imaging

Abstract

High energy, high repetition rates laser with excellent beam quality are fundamental components for LiDAR. In particular, high pulse energy is benefit for long distance range imaging. Narrow pulse width and high repetition rates are benefit for high resolution and high refresh rate operation of LiDAR. However, increasing the laser repetition rates will cause the pulse energy decreasing and the pulse width expanding. In order to achieve the requirements at the same time, we propose a 885 nm laser diode end-pumped RTP Q-switched Nd:YAG laser. Pulse pumping scheme was used to avoid heat accumulation. With a master oscillator power amplifier (MOPA) system, 40.5 mJ, 7.5 ns of 1064 nm pulses were obtained at 2 kHz. The beam quality factor M 2 was measured as 1.60/1.51. Moreover, by frequency doubling with a LBO crystal, 16.4 mJ, 6.5 ns of 532 nm laser with the M 2 factor of 1.52 and 1.50 was obtained. The 1064 and 532 nm pulses are suitable for avalanche photodiode arrays LiDAR and streak tube imaging LiDAR, respectively. The laser system is shown to accomplish high stability from temperature of −10 C to 30 C and vibration frequency of 10 to 100 Hz.

High‐power, continuous‐wave optical parametric oscillator based on MgO:sPPLT crystal

“…Near-infrared lasers have important applications in nonlinear optics, material processing, medical diagnosis, laser ranging, and other fields. [1][2][3][4][5][6] The optical parametric oscillator (OPO) based on the quasi-phase matching (QPM) technology can realize the tuning and expansion of the laser wavelength, which provides more possibilities for laser applications in many fields of science and technology including laser measurement, 7,8 and fingerprint imaging. 9 Periodically poled LiNbO 3 (PPLN), MgO-doped PPLN (PPMgLN), and periodically poled LiTaO 3 (PPLT) crystals are commonly used.…”

Identification of aluminum alloy by laser‐induced breakdown spectroscopy combined with machine algorithm

“…Conventional alloy detection methods include inductively coupled plasma atomic emission spectrometry (ICP‐AES), spark source atomic emission spectrometry (spark‐OES), and X‐ray fluorescence (XRF) 2‐4 . LIBS technology can overcome the limitations of other methods, without the need for cumbersome sample preprocessing, enabling remote, real‐time, and online element detection 5‐10 …”

Sub‐nanosecond, single longitudinal mode laser based on a VBG‐coupled EOQ Nd:YVO4 oscillator for remote sensing

“…The high energy, sub‐nanosecond, single longitudinal mode pulse is especially preferred for long‐distance targets detection and high range resolution. In general, the spatial resolution of LiDAR increases with the decrease of pulse duration, and the detection range increases with the increase of pulse energy 4 . The narrower linewidth of laser is also beneficial to increase the signal‐to‐noise ratio of receiver 5 …”