A calculation of the fringe visibility in a laser-illuminated two-beam interferometer is presented and discussed, The laser is assumed to be oscillating in several adjacent axial modes whose intensities are determined by the Doppler-broadened emission line. An exact expression is given for the visibility as a function of path-length difference, and it is shown to be the product of an exponential envelope and a periodic function whose period is very nearly twice the length of the laser. An important special case is considered to illustrate the values of path-length difference for which the visibility is minimum. Finally, the visibility is plotted in a way which permits estimation of depth of field in holography or acceptable path mismatch in interferometry. For any laser operating in the assumed manner, calculation is simplified by the form of the equations. An example is given.
EDWIN F. ERICKSON and RICHARD M. BROWN, "Calculation of Fringe Visibility in a Laser-Illuminated Interferometer," J. Opt. Soc. Am. 57, 367-368 (1967)