Laser beam profile measurement by photothermal deflection technique

A new method for measuring laser beam profiles using the photothermal deflection technique is reported. The principle of the method is described, and the experimental setup is schematically shown and described. The photothermal deflection (PTD) signal amplitude is plotted against the distance between the centers of the pump and probe beams, and the time-resolved shape of the PTD signal is shown. An expression for PTD signal amplitude based on a simple model is presented whose analytical solution can be found for any type of spatial profile that can be expressed in an analytical form. The theoretical PTD signal amplitude is compared to the experimental result, and good agreement is found.