Intracavity dispersion measurements with a 339-μm He–Ne laser

Abstract
The beat frequency between a (0,0) and a (0,1) mode of a 3.39-μm He–Ne laser is measured as a function of the position of the modes with respect to the line center and for a fixed position as a function of the pressure of CH4 contained inside the cavity. The results suggest that the use of intracavity dispersion is a viable detection technique and furthermore that the dispersion of the gain medium in a dual-polarization laser will not pose a serious limitation to the measurement of intracavity anisotropies.