Simulation and analysis of the time evolution of laser power and temperature in static pulsed XPALs

Chenyi Su,Binglin Shen,Chunsheng Xia,Xingqi Xu,Bailiang Pan

doi:10.1017/hpl.2019.28

Abstract

A theoretical model is established to describe the thermal dynamics and laser kinetics in a static pulsed exciplex pumped Cs–Ar laser (XPAL). The temporal behaviors of both the laser output power and temperature rise in XPALs with a long-time pulse and multi-pulse operation modes are calculated and analyzed. In the case of long-time pulse pumping, the results show that the initial laser power increases with a rise in the initial operating temperature, but the laser power decreases quickly due to heat accumulation. In the case of multi-pulse operation, simulation results show that the optimal laser output power can be obtained by appropriately increasing the initial temperature and reducing the thermal relaxation time.

Highlights

An optically pumped atomic Rb vapor laser operating on the resonance at 795 nm, the diode-pumped alkali vapor laser (DPAL), was first realized by Krupke et al in 2003[1]
Researchers noticed that an unavoidable drawback in DPAL hindered its development
The narrow linewidth of alkali atomic absorption (∼0.02 nm) means only few commercial semiconductor lasers can be chosen as effective pump sources for DPAL systems due to the spectrally resolved width of commercial laser diodes being on the order of magnitude of 1 nm[2]

Summary

Introduction

An optically pumped atomic Rb vapor laser operating on the resonance at 795 nm, the diode-pumped alkali vapor laser (DPAL), was first realized by Krupke et al in 2003[1]. The narrow linewidth of alkali atomic absorption (∼0.02 nm) means only few commercial semiconductor lasers can be chosen as effective pump sources for DPAL systems due to the spectrally resolved width of commercial laser diodes being on the order of magnitude of 1 nm[2] To address this issue, adding high-pressure helium, 19,000–38,000 Torr (1 Torr = 133.32 Pa), to broaden the linewidth was proposed by Krupke et al.[3]. The results showed that due to the high heat loading generated by multiple transitions, a sharp temperature gradient occurs in the cell, which may cause the experimental device to melt down and the stimulated emission to quench They introduced gas flow into the system to reduce the temperature gradient[13] and applied fluid methods to the CW XPAL system, with good simulation results being achieved[14].

Description of model and kinetic processes

Calculation of three-dimensional heat conduction and temperature distribution

Results and discussion

Conclusion