Patent ID: 6693848
Filing Date: 2004-02-17
Classification: G01H,G01V

Abstract:
An optical apparatus for detecting seismic vibrational energy comprising:a fixed length cavity laser material exhibiting birefringence which generates two orthogonal lasing frequency signals lasing at different frequencies, a beat frequency between the two frequencies which varies in accordance with vibrational energy incident upon the laser material, wherein the vibrational energy is incident upon a side of the laser material orthogonal to the incidence of excitation energy, wherein the vibrational energy stresses the laser material; a light source occurring at an excitation frequency for providing the excitation energy incident upon the laser material, so that the laser material emits light at the beat frequency modulated by the vibrational energy; and a fiber optic cable for transmitting the excitation frequency light to the laser material and receive the frequency modulated lasing frequency for transmission to a receiver.