Optics and Photonics Society of Iran

In the measurement of the vibration characteristics of the gain medium in thin disk laser, the homodyne Laser Doppler vibrometry was applied. For recognition of the direction of motion of the vibrating element, we developed the N-point spatial phase shift technique to identify the direction of motion of the linear interference fringes. After experimentally establishing the method, in a special case of 3-point technique, it was applied on the measurement of the vibration characteristics of the gain medium in thin disk laser. The results revealed the random nature of the vibration that can be analyzed through non-stationary signals analysis methods such as short time Fourier transform or wavelet transform. The results of such analysis can be used in the optimizing the laser design.