A tunable laser device produces a laser energy over a range of frequencies. A
property
of an ultrasonic transducer or, more specifically, the frequency of an ultrasonic
wave created by the ultrasonic transducer is altered to change the laser frequency
of the tunable laser device. The ultrasonic transducer may couple its ultrasonic
wave directly into the laser source or may form a tunable acousto-optic modulator
external to the laser source. In both cases, the ultrasonic wave creates an index
of refraction perturbation in an optical substrate, through which the laser energy
of the laser source passes. Changes in the ultrasonic wave cause changes in the
perturbation through which the laser energy passes, which in turn, changes the
frequency of the laser energy, thereby enabling the frequency of the laser to be tuned.
