Self-phase modulation resulting from radiation influence on material p
arameters of a medium can, like the Doppler and gravitational redshift
s, result in a nearly uniform frequency shift. This is confirmed exper
imentally by the use of the orientational mechanism of the interaction
of a laser beam with a nematic liquid crystal. The self-induced frequ
ency shift is proportional to light intensity and the distance light t
ravels in the medium.