US 12,468,266 B1
Dual frequency laser for dual mode optical lattice atomic clock
Jie Ren, Xi'an (CN); and Hong Chang, Xi'an (CN)
Assigned to NATIONAL TIME SERVICE CENTER, CHINESE ACADEMY OF SCIENCES, Xi'an (CN); and HEFEI NATIONAL LABORATORY, Hefei (CN)
Filed by NATIONAL TIME SERVICE CENTER, CHINESE ACADEMY OF SCIENCES, Shaanxi (CN); and HEFEI NATIONAL LABORATORY, Anhui (CN)
Filed on Jun. 19, 2025, as Appl. No. 19/243,685.
Claims priority of application No. 202411274715.6 (CN), filed on Sep. 12, 2024.
Int. Cl. G04F 5/14 (2006.01); H01S 3/094 (2006.01); H01S 3/137 (2006.01)
CPC G04F 5/14 (2013.01) [H01S 3/094069 (2013.01); H01S 3/137 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A dual frequency laser for a dual mode optical lattice atomic clock, wherein the dual frequency laser comprises a 532 nm pump laser source, and in an emission optical path of the 532 nm laser, a beam splitter set, a dichroic mirror, a titanium sapphire crystal, a birefringent crystal, an electro-optic crystal, a concave reflector, and piezoelectric ceramics (PZT) are disposed sequentially, wherein
the dichroic mirror and the concave reflector form a first resonant cavity configured to generate a laser;
the beam splitter set is configured to split a collimated pump beam into two pump beams that are spatially separated;
an optical axis of the birefringent crystal is at an angle of 45° to a light incidence plane to generate propagation paths for ordinary ray and extraordinary ray within the same cavity to form two eigen modes; in each of the propagation paths for ordinary ray and extraordinary ray, a set of birefringent filter and etalon is provided, an anti-reflective coating of the birefringent filter and a high-reflective coating of the concave reflector have spectral bands with overlapping edges, the spectral bands being used for a rough selection of a laser wavelength, and the etalon and the birefringent filter being used for a mode fine selection;
the electro-optic crystal is configured to add an electric field externally in a direction parallel to an electric vector of the ordinary ray or an electric vector of the extraordinary ray to independently regulate a frequency of one polarized ray; and
the piezoelectric ceramic is combined with the electro-optic crystal to regulate two laser frequencies simultaneously.