Photon-counting phase-stabilized dual-comb ranging.

Dual-comb ranging (DCR), with its superior overall performance compared to traditional ranging technologies, has recently attracted widespread interest in the research community. Nevertheless, the ranging distance or the material of the targets is limited by the detection sensitivity of optical asynchronous linear sampling. This limitation restricts the application of DCR in several highly significant scenarios.

Single-photon avalanche diodes dynamic range and linear response enhancement by conditional probability correction.

Detectors based on single-photon avalanche diodes (SPADs) operating in free-running mode surfer from distorted detection signals due to the impact of afterpulse, dead time, and the non-linear detection efficiency response. This study presents a correction method based on conditional probability. In the experiments with high temporal resolution and huge dynamic range conditions, this method's residual sum of squares is near 68 times smaller than the uncorrected received data of SPAD and near 50 times smaller than deconvolution method.

Denoising coherent Doppler lidar data based on a U-Net convolutional neural network.

The coherent Doppler wind lidar (CDWL) has long been thought to be the most suitable technique for wind remote sensing in the atmospheric boundary layer (ABL) due to its compact size, robust performance, and low-cost properties. However, as the coherent lidar exploits the Mie scattering from aerosol particles, the signal intensity received by the lidar is highly affected by the concentration of aerosols. Unlike air molecules, the concentration of aerosol varies greatly with time and weather, and decreases dramatically with altitude.

Mitigation of amplified spontaneous emission noise for an all-fiber coaxial aerosol lidar with different single-photon detectors.

For a coaxial single-photon lidar system, amplified spontaneous emission (ASE) noise from the fiber amplifier is inevitable. The ASE backscattering from specular reflection annihilates the far-field weak signal, resulting in low signal-to-noise ratio, short measurement distance, and even misidentification. We propose a method for calibrating and mitigating ASE noise in all-fiber coaxial aerosol lidar and demonstrate the method for a lidar system with different single-photon detectors (SPDs).

Meter-scale and sub-second-resolution coherent Doppler wind LIDAR and hyperfine wind observation.

Hyperfine wind structure detection is important for aerodynamic and aviation safety. Pulse coherent Doppler wind LIDAR (PCDWL) is a widespread wind remote sensing method with tunable spatial and temporal resolutions. However, meter scale and sub-second resolution are still challenging for PCDWL.

Metastable helium Faraday filter for helium lidar to measure the density of the thermosphere.

We demonstrate a metastable helium Faraday optical filter operating on the 2S - 2P and 2S - 2P transition at 1083 nm by using a 3 cm long helium cell. The influence of the magnetic field and gas pressure of the helium cell on the filter characteristics is experimental studied. When the magnetic field is 230 Gs and the gas pressure of helium cell is about 110 Pa, the peak transmission corresponding to the two energy level transitions is about 32% and 57%, respectively.

Fine gust front structure observed by coherent Doppler lidar at Lanzhou Airport (103°49$^{\prime}$E, 36°03$^{\prime}$N).

Coherent Doppler lidar (CDL) has long been used to automatically identify gust front-induced wind shear signatures from the velocity data, but rare attention has been given to the fine structure of wind gust fronts. In this work, a compact and robust CDL with high efficiency and accuracy is equipped at Lanzhou Airport (103°49$^{\prime}$E, 36°03$^{\prime}$N) to conduct interpretation of wind gust front structures by using high-resolution CDL data. Outflows of gust fronts could be detected reliably from radial velocities, spectral widths, as well as radial shears.

Gravity waves observation of wind field in stratosphere based on a Rayleigh Doppler lidar.

Simultaneous wind and temperature measurements in stratosphere with high time-spatial resolution for gravity waves study are scarce. In this paper we perform wind field gravity waves cases in the stratosphere observed by a mobile Rayleigh Doppler lidar. This lidar system with both wind and temperature measurements were implemented for atmosphere gravity waves research in the altitude region 15-60 km.