Precise measurement of the micron scale spot of ultrashort laser pulse based on

A novel and precise micron-scale nanosecond laser spot measurement based on film-scanning method is presented. The method can be used to measure the spot size, beam profile, and intensity distribution of the pulse. The central spot radius of the pulsed Bessel beams with pulse width of 25 ns is measured to be 94.86+-5 \mum in our experiment through the analysis of the digital image by film scanning, and the result is consistent with the theoretical value of 92.33 \mum. Compared with charge-couple