Photoacoustic methods for real‐time measurement of laser beam diameter and position, and for laser cavity alignment

Photoacoustic signals generated in absorbing media can be used for real‐time alignment of laser cavity components, for measurements of positions and diameters of pulsed laser beams, and for control of the degree of overlap of two or more, focused and unfocused pulsed laser beams. The developed techniques require an absorbing medium and a piezoelectric detector. Measurements and control can be performed by real‐time inspection of the acoustic signals in an oscilloscope. These methods are convenient for experiments in nonlinear optics in which the power requirements lead to focusing and superposition of the beams, and for alignment of laser cavities in the liquid phase as well as gas and solid state infrared lasers. © 1995 American Institute of Physics.