The propagation of focused beams having an on-axis irradiance null is considered in the presence of thermal blooming. Two cases are treated: (a) beam profiles that have an irradiance zero in the beam center at the focal plane as well as the transmitter aperture; (b) beam profiles that have an on-axis irradiance null only at the transmitter. It is demonstrated that none of the beam profiles considered in case (a) has a meaningful advantage over a Gaussian beam profile. Some of the case (b) profiles do produce a larger bloomed irradiance in the focal plane, particularly when the initial intensity distribution is very uniform in its nonzero regions. Addition of a simple central obscuration to a “filled” irradiance distribution is found to have no advantage, however, for the cases considered.
© 1976 Optical Society of America
Equations on this page are rendered with MathJax. Learn more.