Temperature and Input Energy Dependence of the 946-nm Stimulated Emission Cross Section of Nd ³⁺ :YAG Pumped by a Flashlamp

Abstract

The thermal effect on the laser transition at 946 nm is investigated. The temperature of the cooling system is verified in the range 2–60°C. A Nd:YAG laser crystal is utilized as a gain medium and is pumped by a newly developed flashlamp. The variable pumping energy is accomplished within the 5–40 J range. The stimulated emission cross section of the 946-nm line is estimated based on the fluorescence spectrum of the Nd:YAG laser. The stimulated emission cross section of the 946-nm line is found to be inversely proportional to the temperature and to the input energy due to the increase of the thermal population at the ground level.

Stimulated emission cross section at various temperatures based on laser performance

“…Figure 7 shows the P out / f 1 versus absorbed pump power graph at various temperatures. Through (11), the stimulated emission cross section parallel to the c-axis of Nd:YVO 4 was determined at each temperature, as shown in figure 8. From figure 8, we can see that the stimulated emission cross section decreased linearly as the temperature increased at a rate of 6.0 × 10 −21 cm 2 °C−1 .…”

“…Variations in the stimulated emission cross section of Nd-doped gain mediums with temperature were determined through these methods in previous studies, e.g. Nd:YVO 4 [5][6][7], Nd:GSGG [8], Nd 3+ doped phosphate glasses [9], Nd:GdVO 4 [10], Nd:YAG [11], ceramic Nd:YAG [12] and Nd:CaYAlO 4 [13]. The spectroscopic method requires a spectrometer and complicated analysis.…”

Effects of 946-nm thermal shift and broadening on Nd 3+ :YAG laser performance

“…The flashlamp was pumped by a homemade power supply. [20] The driver was triggered by a simmer mode technique. A capacitor bank with a capacitance of 150 µF was charged from zero volt up to a maximum voltage of 1200 V, thus the input energy was varied between 0 J to 100 J.…”

Determination of a stimulated emission cross section gradient on the basis of the performance of a diode-end-pumped Nd:YVO4laser

“…Furthermore, in most high-power solid state lasers, variation of the emission cross section with the temperature has a serious effect on the laser performance. Spectroscopic properties and stimulated emission cross sections of Nd:YAG crystals at various temperatures have been studied extensively [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Commonly, the temperature under study is in the range of 77-350 K. In this method, parameters such as the emission linewidth, branching ratio and intensity of the emission lines are acquired from fluorescence spectra in order to calculate the stimulated emission cross section at the respective temperature through the Fuchtbauer-Ladenburg (F-L) formula.…”