• Korean Journal of Optics and Photonics
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• v.33 no.1
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• pp.1-10
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• 2022

In this study we introduce a new method for high-spatial-resolution continuous wave (CW) aerosol lidar that has a high spatial resolution in the near field and a low spatial resolution at long distances. A normal lidar system uses a nanosecond-pulse laser and measures the round-trip TOF between the aerosol and laser to obtain range resolution. In this study, however, we propose a new type of spatially resolving aerosol lidar that uses laser-scattering images. Using a laser-light-scattering image, we have calculated the distance of each scattering aerosol image for a given pixel, and recovered the short-range aerosol extinction. For this purpose, we have calculated the distance image and the contribution range of the aerosol to the given one-pixel image, and finally we have calculated the extinction coefficients of the aerosol with range-resolved information. In the case of traditional aerosol lidar, we can only obtain the aerosol extinction coefficients above 400 m. Using our suggested method, it was possible to extend the range of the extinction coefficient lower then several tens of meters. Finally, we can remove the unknown short-range region of pulsed aerosol lidar using our method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.656-661
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• 2002

Multipass Ti:sapphire amplifier for the light source of lidar was developed in an angular-multiplexing, and the characteristics of output energy and spectrum was investigated. In the two-stage multipass amplifier, we obtained the maximum output energy of 42 mJ, the amplification gain of 21 dB and the output efficiency of 26% on the wavelength of 790 nm. In the tuning range of 715~930nm the spectral linewidth is 0.05 $cm^{-1}$ /. The conversion efficiencies of 35% for SHG at 780 m and 13% for THG at 390 nm are obtained respectively. The continuous tunabilities of 240~306 m UV region and 360~460 nm in deep-blue region could be achieved.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.6
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• pp.1023-1030
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• 2023

FMCW LiDAR system with robust target detection capabilities even under adverse operating conditions such as snow, rain, and fog is addressed in this paper. Our focus is primarily on enhancing the performance of FMCW LiDAR by improving the characteristics of the frequency-modulated laser, which directly influence range resolution, coherence length, and maximum measurement range etc. of LiDAR. We describe the utilization of an unbalanced Mach-Zehnder laser interferometer to measure real-time changes of the lasing frequency and to correct frequency modulation errors through an optical phase-locked loop technique. To extend the coherence length of laser, we employ an extended-cavity laser diode as the laser source and implement a laser interferometer with an photonic integrated circuit for miniaturization of optical system. The developed FMCW LiDAR system exhibits a bandwidth of 10.045GHz and a remarkable distance resolution of 0.84mm.