Simultaneous detection of the Ca and Ca⁺ layers by a dual-wavelength tunable lidar system

Abstract

A dual-wavelength tunable lidar system that simultaneously detects the Ca and C a + layers has been established in Yanqing Station (40.41°N, 116.01°E). The lidar system implements a pulsed Nd:YAG laser that simultaneously pumps two dye lasers, which reduces the hardware configuration of the lidar system. The two dye lasers use infrared laser dyes with high conversion efficiency suitable for long-term observation. The resonance wavelengths of Ca and C a + are generated by frequency doubling of the two infrared laser beams. We compared the dual-wavelength tunable lidar system to previous dye-based systems and performed experiments to determine resonance frequencies to within 0.4 pm and to test the dual optical fiber receiving system and found it does not cause cross talk. Three nights of preliminary simultaneous observations of Ca and C a + layers are reported; the diversity of these observations begs for more systematic observations and challenging interpretations in terms of Ca processes in the ionosphere and illustrates the effectiveness of this system for aeronomy and space physics studies.

Role Of the Sun and the Middle atmosphere/thermosphere/ionosphere In Climate (ROSMIC): a retrospective and prospective view

“…Recent highresolution Ca + density measurements revealed various structures and the evolution of the Ca + layer between 80 km and 180 km altitudes. These results provide information on the coupling of the E and F regions (Ejiri et al 2019b;Ejiri et al 2019a;Raizada et al 2020;Wu et al 2020). Recently, mesospheric Ni layers were also detected by lidar over Alaska and Germany (Collins et al 2015;Gerding et al 2019).…”

First Lidar Profiling of Meteoric Ca+ Ion Transport From ∼80 to 300 km in the Midlatitude Nighttime Ionosphere

“…The Ca + measurements were made with an upgraded resonance‐fluorescence dual‐wavelength Ca + /Ca lidar at Yanqing Station (40.42°N, 116.02°E) near Beijing. Two broadband pulsed dye lasers employed in the original Ca + /Ca lidar system (Wu et al., 2020) were replaced with two solid‐state, injection‐seeded, and pulsed Optical Parametric Oscillator (OPO) lasers in March 2020. The two OPO lasers were tuned to wavelengths of 393.4777 and 422.7918 nm (in vacuum) for exciting resonance fluorescence of Ca + and Ca, respectively.…”

The All-Solid-State Narrowband Lidar Developed by Optical Parametric Oscillator/Amplifier (OPO/OPA) Technology for Simultaneous Detection of the Ca and Ca+ Layers

“…This section will focus on the laser emission system, which is the key part of the OPO Lidar design. The receiving and acquisition system will be briefly described, whose technical details have been discussed previously in the dual-wavelength tunable lidar system of a Ca and Ca + layer detector [15].…”

“…Their research showed a regular altitude relationship, in which Na s is highest, Fe s is a few to tens of hundreds of meters lower than Na s , Ca s is a few hundred meters lower than Fe s , and Ca s + is the lowest. Wu et al [15] reported a dual-wavelength tunable lidar system to detect Ca and Ca + at Yanqing Station (40.41 • N, 116.01 • E). Their lidar system implemented a pulsed Nd:YAG laser that simultaneously pumps two dye lasers, and completes simultaneously to detect Ca and Ca + .…”