Studies on gain medium inhomogeneity and spectral fluctuations coupled with a high repetition rate dye laser

Abstract

Gain medium inhomogeneity is inevitable in a high repetition rate dye laser. In this paper, gain medium inhomogeneity coupled with a high repetition rate dye laser and their influences on the spectral fluctuations are investigated. The wavelength fluctuates within ±0.025 nm while the bandwidth fluctuates within ±1.108 GHz by reducing the flow Reynolds number from 1012 to 221 in the laminar region of flow. The wavelength fluctuations increase from 0.0110 to 0.0200 nm while the bandwidth fluctuations increase from 0.296 to 0.509 GHz by increasing the Reynolds number from 5645 to 6774 in the turbulent region. The heat deposition as a function of distance from the window wall in the gain medium and heat transfer coefficients as a function of Reynolds numbers in laminar and turbulent flow were estimated. Enlargement of the turbulent attribute (through a laminar sub-layer and buffer region) in the gain medium as a function of the Reynolds number was used to illustrate the observed spectral fluctuation trends of the dye laser.