Development of a tunable, narrow-linewidth, cw 2066-μm Ho:YLF laser for remote sensing of atmospheric CO_2 and H_2O

Abstract

A smoothly tunable, narrow-linewidth, cw, 32-mW, 2.066-mum Ho:YLF laser was constructed and used for the first time in preliminary spectroscopic measurements of atmospheric CO(2) and H(2)O. The laser was constructed with a 4.5-mm-long, TE-cooled, codoped 5% Tm and 0.5% Ho yttrium lithium fluoride crystal (cut at Brewster's angle) pumped by an Ar(+)-pumped 500-mW Ti:sapphire laser operating at 792 nm. Intracavity etalons were used to reduce the laser linewidth to approximately 0.025 cm(-1) (0.75 GHz), and the laser wavelength was continuously and smoothly tunable over approximately 6 cm(-1) (180 GHz). The Ho:YLF laser was used to perform spectroscopic measurements on molecular CO(2) in a laboratory absorption cell and to measure the concentration of CO(2) and water vapor in the atmosphere with an initial accuracy of approximately 5-10%. The measurement uncertainty was found to be due to several noise sources, including the effect of asymmetric intensity of the laser modes within the laser linewidth, fluctuations caused by atmospheric turbulence and laser beam/target movement, and background spectral shifts.

121 W passively mode-locked Tm:LuAG laser

“…Ultrafast all-solid-state lasers operating in 2 micrometer spectral regions have well-known wide applications in the fields of industry, defense, medical treatment, and scientific research [1][2][3][4]. Mode-locking Tm 3+ doped bulk lasers provide ideal approaches to achieve such kind of lasers, especially with the aids of passive mode-locking method based on saturable absorption, which has gained its popularity in generating ultrafast 2 μm lasers due to the advantages of simplicity, compactness, reliability and the ability to generate ultrashort pulses [5].…”

High repetition rate, Q-switched Ho:YAG laser resonantly pumped by a 20 W linearly polarized Tm: fiber laser

“…They are required for remote sensing [2] and the monitoring of atmospheric CO 2 and H 2 O [3,4], wind measurements, as well as for long distance range finders. They offer unique and exceptional properties which are required in such applications as material processing or laser surgery and therapy [5][6][7].…”

Pump excited state absorption in holmium-doped fluoride glass

“…The geometry and size of the fiber waveguide means that they are comparatively less affected by thermal problems and a high spatial quality output beam can typically be produced at very high output power levels. 1 Many applications such as laser surgery [2][3][4] and remote sensing [5][6][7] are dependent on high power midinfrared radiation and, as a result, there exists a strong demand for the development of high power and efficient midinfrared laser devices. A midinfrared fiber laser that offers high power and high efficiency remains a technological challenge; however, a number of interesting and potentially power scalable midinfrared fiber laser alternatives, which operate at the short wavelength region of the midinfrared spectrum ͑at ϳ3 m͒ have been demonstrated.…”