Diffraction and shaping analysis of excimer laser through an ultrasonic grating

• A novel numerical simulation method for the shaping of an excimer laser beam by an acoustic grating is proposed.
• The influence of different parameters on the uniformity of intensity distribution of excimer laser is analyzed.
• A group of parameters to produce a flat top beam for V=1.5, Z=1.05 m, and f=57 MHz is obtained.
• The results are used as an effective analytic tool for the determination of the design parameters of acousto-optic modulator.

A novel numerical simulation method for the shaping of an excimer laser beam by an acoustic grating is proposed. Partially coherent theory and extended Huygens–Fresnel principle are used to analyze the light intensity diffraction pattern. Fast Fourier transform function FFT in the Matlab is used to calculate the numerical integral, which makes the integral operation simple and efficient. It is shown by a numerical simulation that the output intensity distribution is closely related to the coherence width, Raman–Nath comprehensive parameter, diffraction distance and ultrasonic wave frequency. The simulation results show that a flat top beam can be obtained by controlling these parameters. On the other hand, the results are used as an effective analytic tool for the determination of the design parameters of acousto-optic modulator.