CC BY
19LD-O-7
A 3-ns pulsed diode laser for a high spatial resolution lidar
S. M. Pershin1, M.Ya. Grishin1, V. A. Zavozin1, V. S. Makarov2, V. N. Lednev1, A.V.
Myasnikov3, A.V. Turin2
1-Prokhorov General Physics Institute of the Russian Academy of Sciences, 119991 Moscow, 38 Vavilova
street, Russia
2-Space Research Institute of the Russian Academy of Sciences, Moscow, Russia 3-Sternberg Astronomical Institute Moscow State University Moscow, Russia
E-mail: pershin@kapella.gpi.ru
We report on achieving the generation of 3 ns pulses by an AlGaAs semiconductor laser (907 nm, 0.2 Jpulse) with eye-safe energy density (< 1 Jcm2) suitable for lidar sensing. The laser consists of three stacked emitters in a plastic case. An external current pump generator was assembled on a printed circuit board along with the laser from commercially available discrete elements with a bipolar FMMT417 transistor as a key.
Using such a laser, a lidar based on a single photon avalanche photodiode (SPAD) was constructed. Fig.1(a) shows a lidar histogram (range distribution of backscattered photons) for measuring distance to a flat wall at ~33 m. In this experiment the laser emitted 50000 pulses and the range resolution was 10 cm. One can see from Fig.1(a) that the lidar histogram is asymmetric just like the laser pulse shape on the oscillogram in Fig.1(b). Such pulse shape is characteristic for diode lasers pumped by the capacitor discharge [1].
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Fig. 1. (a) Laser pulse in the form of lidar photocount histogram, (b) laser pulse oscillogram measured by the Aktakom ADS-2332 oscilloscope (300 MHz bandwidth), (c) comparison of magmatic aerosol lidar sensing data (lower curve) and the seasonal Earth's crust deformation measured by a laser strainmeter (upper curve) at October 27-30, 2019.
The lidar based on the described laser and a SPAD detector provided monitoring of magmatic aerosols with 10 cm spatial resolution inside a dead-end adit in the Baksan Neutrino Observatory near the Elbrus volcano (43°14'57.7"N, 42°43'19.5"E). The lidar performed a measurement every 30 minutes by accumulating 100000 laser pulses. For the first time a 3-fold "jump" of the magmatic aerosol output has been detected (see Fig.1(c)) [2]. The nature of this "jump" remains unclear. Note that laser strainmeter with 1.6-10-11 m sensitivity [3] have not detected any traces of the Earth's crust deformation at this time, which proves the lidar as a new, highly sensitive instrument for studying geodynamic processes.
The authors are grateful for the Russian Science Foundation for the financial support of the study (project №19-19-00712).
[1] Slipchenko S.O., Podoskin A.A., Soboleva O.S., Pikhtin N.A., Bagaev T.A., Ladugin M.A., Marmalyuk A.A., Simakov V.A., Tarasov I.S. Generation of nanosecond and subnanosecond laser pulses by AlGaAs/GaAs laser-thyristor with narrow mesa stripe contact. Optics Express, 24, 16500 (2016).
[2] Pershin S.M., Sobisevich A.L., Grishin M.Ya., Gravirov V.V., Zavozin V.A., Kuzminov V.V., Likhodeev D.V., Lednev V.N, Makarov V.S., Myasnikov A.V., and Fedorov A.N., Volcanic activity monitoring by unique LIDAR based on a diode laser, Laser Phys. Lett. 17(11), 115607 (7pp), (2020).
[3] Milyukov V.K., Myasnikov A.V., "Metrological characteristics of the Baksan laser interferometer," Measurement Techniques, Instrument Society of America, vol. 48, no. 12, pp. 1183-1190, (2012).
