Influence of sample temperature on the expansion dynamics of laser-induced germanium plasma

In this paper, we investigated the influence of sample temperature on the expansion dynamics and the optical emission spectroscopy of laser-induced plasma, and Ge was selected as the test sample. The target was heated from room temperature (22 °C) to 300 °C, and excited in atmospheric environment by using a Q-Switched Nd:YAG pulse laser with the wavelength of 1064 nm. To study the plasma expansion dynamics, we observed the plasma plume at different laser energies (5.0, 7.4 and 9.4 mJ) and different sample temperatures by using time-resolved image. We found that the heated target temperature could accelerate the expansion of plasma plume. Moreover, we also measured the effect of target temperature on the optical emission spectroscopy and signal-to-noise ratio.