Generation of high-order Hermite-Gaussian modes in a flashlamp-pumped neodymium phosphate glass laser and their conversion to Laguerre-Gaussian modes

The Hermite-Gaussian modes up to the third order inclusive are generated in a flashlamp-pumped neodymium phosphate laser and converted to the corresponding Laguerre-Gaussian modes in an astigmatic pi/2 converter. It is also shown that, by using a laser with the gain minimum on the axis of a plane-spherical resonator and changing its Fresnel number, it is possible to excite efficiently Laguerre-Gaussian modes with the field amplitude dependence similar to(sin)(cos)(l phi).