The effect of an electric field on the active medium in a dye laser

We investigate the effect of subjecting the active medium (rhodamine 6G in methanol) in a dye laser to an applied electric field. When the optical configuration is for broad-band output, an overall broadening of the output proportional to the square of the field is observed. No shift is obtained. The magnitude of this effect (
7.4 \times 10^{-8}
cm
^-1
(V/cm)
^-2
) is much too large to be explained by the normal Stark broadening of spectral output due to a dipolar change on excitation. When a grating and beam expander are inserted into the cavity to create narrow spectral output it is found that the relative intensities of transverse modes can be controlled by variations in the applied field.