Abstract: The frequency stability of an optical local oscillator is improved by locking a laser to a silicon Fabry-Perot cavity operating at a temperature near 124 K, where the coefficient of thermal expansion of silicon is near zero. The cavity is mounted inside a cryostat housed in a temperature-stabilized vacuum system that is surrounded by an isolating enclosure and supported by an active vibration platform. Laser light is steered with a superpolished mirror toward a superpolished focusing optic that couples the laser light into the cavity. Light reflected from the cavity is used to stabilize the laser via the Pound-Drever-Hall technique, while light transmitted through the cavity is used to stabilize the laser power. A resonant transimpedance amplifier allows the laser power to be reduced, which reduces heating of the cavity caused by residual absorption of the light.
Type:
Grant
Filed:
December 18, 2020
Date of Patent:
June 7, 2022
Assignees:
The Regents of the Univ. of Colorado, a body corp., Government of the United States of America, as represented by the Secretary of Commerse
Inventors:
Jun Ye, Eric G. Oelker, William R. Milner, John M. Robinson, Colin J. Kennedy, Tobias Bothwell, Dhruv Kedar, Terry Brown