Water vapor differential absorption lidar measurements using a diode-pumped all-solid-state laser at 935 nm

Abstract

A diode-pumped, single-frequency laser system emitting at 935 nm has recently been developed to serve as the transmitter for water vapor differential absorption lidar (DIAL) measurements. This laser uses Nd:YGG (Y 3 Ga 5 O 12 ) as the active medium and emits radiation directly at 935 nm without the need of additional frequency conversion processes. The system was diode-pumped at 806 nm and was built up in a master-oscillator-poweramplifier configuration. It generates more than 30 mJ of pulse energy at 100 Hz repetition rate with a beam quality (M 2 ) of better than 1.4. Since water vapor DIAL demands for stringent requirements of the spectral properties those were carefully investigated in the scope of this paper. Single-frequency operation is achieved by injection seeding and active length control of the oscillator cavity. to ∼0.4 nm centered around 935.31 nm. Values of the spectral purity of >99.996% were determined using long-pass absorption measurements in the atmosphere exceeding the requirements by a large margin. Finally, for the first time water vapor DIAL measurements were performed using a Nd:YGG laser. The reported results show much promise of these directly pumped lasers at 935 nm for future spaceborne but also airborne water vapor lidar systems.

3-D water vapor field in the atmospheric boundary layer observed with scanning differential absorption lidar

“…Specific DIAL systems were developed, e.g., near 720 nm (Bruneau et al, 2001;Wulfmeyer and Bösenberg, 1998), near 820 nm (Ismail and Browell, 1989;Ertel, 2004;Schiller et al, 2007;Vogelmann et al, 2008;Behrendt et al, 2009;Spuler et al, 2015), near 935 nm (Machol et al, 2004(Machol et al, , 2006Wirth et al, 2009;Fix et al, 2011), and near 1480 nm (Petrova-Mayor et al, 2008). The UHOH DIAL operates at wavelengths near 818 nm because this wavelength region can be reached well with a Ti:sapphire transmitter and offers a sufficiently large range of WV absorption cross sections (Wagner et al, 2011.…”

Stable and tunable single frequency Nd:GSAG laser around 943 nm

“…Injection-seeded Nd:YGG lasers at 935 nm [7,12] and injection locking of Nd:YAG lasers at 946 nm were reported [13][14][15]. INNOSLAB-based MOPA design was applied to a Nd:YGG oscillator to scale the output pulse energy to 30 mJ [16,17]. Nd:GSAG has been studied in our laboratory and the single frequency operation was obtained recently [9][10][11]18,19].…”

High-brightness all semiconductor laser at 1.57 μm for space-borne lidar measurements of atmospheric carbon dioxide: device design and analysis of requirements

“…The attenuation from CO 2 be calculated by the power ratio of the back-scattered signals at the end of the optical path and can be converted into a column-averaged mixing ratio thanks to the knowledge of the path length from the round-trip time delay. Typical laser sources currently used in IPDA lidars are solid state lasers working in pulsed regime, emitting ns pulses with high energy at low to medium repetition rate (typical values are 10-50 ns, ~10-50 mJ, 50-200 Hz) [3,4]. Although these laser systems have demonstrated the high average power, high laser beam quality and frequency stability required by the application, it is at the expense of a bulky system with low wall plug efficiency, which is a main concern for space-borne applications.…”