DIFFRACTION OF HERMITE GAUSSIAN BEAMS FROM A SINUSOIDAL CONDUCTING GRATING

The diffraction of E-polarized Hermite-Gaussian beams of arbitrary order from a sinusoidal conducting grating is analyzed by using the plane-wave-spectrum representation for the incident beam field and the space harmonic solutions of the diffracted field for plane-wave incidence. It is shown that both the spot size and the location of the beam waist affect the diffraction characteristics. For the fundamental beam incidence, there exist major peaks in the far-field diffraction pattern, and the angle of the maximum value of each peak coincides with that of one of propagation space harmonics that will be produced when a plane wave is incident parallel to the beam axis. The decrease of the spot size makes the width of each peak broaden. For the first-order beam incidence, a deep dip is observed at each major peak. This dip is caused by the zero on the beam axis in the amplitude distribution of the incident beam field. © 1990 Optical Society of America.