Magnetic-enhanced modulation transfer spectroscopy and laser locking for ⁸⁷Rb repump transition

Abstract

Locking of a laser frequency to an atomic or molecular resonance line is a key technique in applications of laser spectroscopy and atomic metrology. Modulation transfer spectroscopy (MTS) provides an accurate and stable laser locking method which has been widely used. Normally, the frequency of the MTS signal would drift due to Zeeman shift of the atomic levels and rigorous shielding of stray magnetic field around the vapor cell is required for the accuracy and stability of laser locking. Here on the contrary, by applying a transverse bias magnetic field, we report for the first time observation of a magnetic-enhanced MTS signal on the transition of 87 Rb D2-line Fg = 1 → Fe = 0 (close to the repump transition of Fg = 1 → Fe = 2), with signal to noise ratio larger than 100:1. The error signal is immune to the external magnetic fluctuation. Compared to the ordinary MTS scheme, it provides a robust and accurate laser locking approach with more stable long-term performance. This technique can be conveniently applied in areas of laser frequency stabilization, laser manipulation of atoms and precision measurement.

Low noise phase-locked laser system for atom interferometry

“…1, our 780 nm laser system for atom interferoemtry is based on the frequency doubling of two 1560 nm seed lasers, one of which is a narrow linewidth (0.83 kHz) distributed feedback fiber laser (DFB FL) with a piezoelectric actuator (PZT) controlled external cavity (NKT Photonics), and the other of which is a narrow linewidth (4.5 kHz) fiber external cavity laser (FECL) with a fixed-length external cavity and a DC-coupled current modulation access (Precilasers). With the magnetic-enhanced modulation transfer spectroscopy (MEMTS) [32], the frequency of the master fiber laser is stablized to the 87 Rb D2 transition |F = 1 → |F ′ = 0 , with respect to which the slave fiber laser is red-detuned by 6.8 GHz.…”

Calibration of a compact absolute atomic gravimeter*

“…[27] All the lasers for operating the atomic gravimeter, including the cooling laser, repump laser, Raman lasers for interference, as well as the detection lasers are provided by the laser module that includes two diode lasers (DL-I and DL-II) and a tapered amplifier (TA). DL-I is locked on 87 Rb transition line by the magnetic enhanced modulation transfer spectroscopy, [28] providing repump laser and one of the Raman lasers. The laser from DL-II is amplified by the TA and phase locked to DL-I with the frequency offset near 6.835 GHz, providing cooling, probe, and the other Raman laser.…”

“…The peak-to-peak variation of the beat frequency is about 160 kHz over 10 hours. [28] So the uncertainty induced by the laser frequency can be estimated as 0.2 µGal.…”

Decay-dephasing-induced steady states in bosonic Rydberg-excited quantum gases in an optical lattice

“…Despite the considered incoherent effects, these schemes may cause additional complications such as atom loss from the optical trap and population of degenerate ground states not considered in the model. While leakage from the considered internal degrees of freedom can be kept under control by a depumping and repumping scheme [40][41][42][43], control of the trap loss is a more demanding task and beyond the scope of the present paper. A possible method to get rid of both effects is to switch to a single-photon excitation scheme instead.…”