Lasers that are equipped with stable optical resonators having large to very large Fresnel numbers and uniform active medium with respect to gain and refractive index, are running multimode, and the highest order transverse mode has the largest mode coefficient. By using this dominant mode feature and an incoherent superposition of the coherent modes, a simple approximate relation was inferred, that allows to estimate beam quality factor M² from the geometrical data of the cavity. A way to evaluate the global degree of coherence of dominant mode laser beams by using a Gauss-Schell model beam having the same beam quality factor M², is proposed.

Date Published: 31 March 1995
PDF: 6 pages
Proc. SPIE 2502, Gas Flow and Chemical Lasers: Tenth International Symposium, (31 March 1995); doi: 10.1117/12.204908

Published in SPIE Proceedings Vol. 2502:
Gas Flow and Chemical Lasers: Tenth International Symposium
Willy L. Bohn; Helmut Huegel, Editor(s)