Abstract

We consider the use of a diffractive optical element (DOE) which simultaneously performs intracavity mode selection and beam shaping of the laser output. Combining these two operations in one device could have considerable benefits in reducing the physical size of the optical setup and in making alignment easier. The mode selecting element (MSE) component of the device allows us to shape the fundamental mode propagating within the cavity. Typically it is desirable to have a super-Gaussian mode with a flat intensity profile. This will achieve much higher energy extraction from the gain medium than a Gaussian TEM mode while also avoiding self focussing effects within the medium. The beam shaping component allows the output intensity profile of the laser to be matched to its application. The layout is illustrated in figure 1. In most applications of MSEs the diffractive structure either replaces the 100% reflective mirror or is a transmission element within the cavity. However, to facilitate e dual purposes of our device it occupies the output coupler position.

© 2007 IEEE