Diode-pumped double-pulsed Ho:Tm:LuLF laser at 2.05 μm for CO 2 differential absorption lidar (DIAL)

Abstract

ABSTRACT It has been realized that eye-safe 2-µ m all-solid-state lasers are important laser sources for an accurate measurement of the CO 2 concentration in the atmosphere. Served as laser transmitters, they can be integrated into ground-based, airborne-base, and spaceborne-based CO 2 Differential Absorption Lidars (DIALs) to accomplish the measurement. In addition, the lasers are also ideal laser pumping sources for a ZnGeP 2 (ZGP) Optical Parametric Oscillator (OPO) or an Optical Parametric Amplifier (OPA) to achieve tunable laser output in 3~5 µ m. In this spectrum region, the other important greenhouse gases, water vapor (H 2 O), carbon monoxide (CO), and methane (CH 4 ) in the atmosphere can be measured. In this paper, we report a diode-pumped, double-pulsed, Q-switched, eye-safe Ho:Tm:LuLF laser at 2.05 µ m developed for ground-based and airborne-based CO 2 Differential Absorption Lidars (DIALs). The technology can be easily transferred to a space-borne CO 2 DIAL in the future. The total output pulse energy of the laser is 220 mJ and 204 mJ per pair of pulses at 2 Hz and at 10 Hz respectively. The related optical energy conversion efficiency is 6.7% and 5.9% respectively. Keywords: Diode pumped laser, 2- µ m lasers, Differential Absorption Lidar (DIAL) 1. INTRODUCTION It has been recognized that the CO