Laser optical system of a rubidium cold-atom interferometer
摘要
The article presents the results of developing a laser optical system for an atom interferometer with rubidium atoms cooled to sub-Doppler temperatures. Developed using quantum technologies, the rubidium cold-atom interferometer is designed to precisely measure the absolute value of gravitational acceleration. The laser optical system, a key part of atom interferometers, is intended to ensure the cooling, pumping, and detection of atoms that interact with optical radiation. The system comprises frequency-doubled fiber lasers and broadband fiber electro-optic modulators. Fiber lasers are used due to their high efficiency, narrow spectral line, low phase noise, as well as their ease of operation and reliability. The laser frequencies are stabilized using modulation transfer spectroscopy and laser frequency phase locking. The authors describe experimental schemes that provide a means to obtain polychromatic radiation and minimize spontaneous scattering due to the laser offset from excitation levels. The design of the laser optical system provides a complete set of optical frequencies required for Raman spectroscopy. The frequency fluctuation amplitudes of the cooling and pumping lasers are studied. The implemented laser optical system is shown to ensure continuous operation of an atom interferometer using clouds of cold rubidium atoms. The fundamental sensitivity limit of the atom interferometer is estimated.