LASER COHERENCE CONTROL USING HOMOGENEOUS LINEWIDTH BROADENING.

摘要

An apparatus and method for linewidth broadening applied to a laser that emits a light having an output frequency nu and an emission linewidth ?E. The apparatus is equipped with an electro-optic modulator for intercepting the light and a noise generator for driving the electro-optic modulator with a radiofrequency (RF) noise signal spanning a frequency range selected to broaden the emission linewidth ?E of the light passing through the electro-optic modulator to a broadened linewidth ?B. The noise spectrum of the noise signal exhibits a continuous frequency range and can be flat or sloping. The range extends from low frequency omegaL set below the emission linewidth ?E of the light to a high frequency omegaH set above the emission linewidth ?E of the light. The electro-optic modulator can be selected from among many suitable devices including optical crystals. Further broadening can be achieved by employing one or more secondary EOMs operating in resonant or non-resonant modes. The lasers that benefit from the invention involve any type of inherently narrow bandwidth lasers operating in CW or pulsed modes.