In atomic physics experiments, a frequency-stabilized or ‘locked’ laser source is commonly required. Many established techniques are available for locking close to an atomic resonance. However, in many instances, such as atomic magnetometer and magic wavelength optical lattices in ultra-cold atoms, it is desirable to lock the frequency of the laser far away from the resonance. This review presents several far off-resonance laser frequency stabilization methods, by which the frequency of the probe beam can be locked on the detuning as far as several tens of gigahertz (GHz) away from atomic resonance line, and discusses existing challenges and possible future directions in this field.

Distributed Bragg reflector (DBR) lasers are widely used in many physics experiments. However, regarding the power and frequency control of DBR lasers, obtaining complete and accurate output characteristics is challenging due to the need for general and accurate quantitative models. In this study, we propose and validate a method based on Gaussian process regression to quickly and accurately establish the DBR laser output power and wavelength model. Two models are developed to describe the output power, wavelength, input current, and temperature. The findings show that our power model explains the laser’s power change from the current threshold to the maximum value more precisely, with a root mean square error (RMSE) of 0.16921 mW, less than one-fifth of that of the classic power model. Moreover, our wavelength model is feasible for accurately describing the laser wavelength with a RMSE of 4×10−4 nm. This study can improve DBR laser power and frequency control efficiency and precision.

With the development of quantum precision measurement technology, measurement methods based on magnetic, optical and atomic interactions have started to receive widespread attention. Among them, quantum precision measurement based on the spin-exchange relaxation-free (SERF) effect shows great potential by its ultra-high measurement sensitivity. This paper introduces the basic operation principles of the magnetic field and inertia measurement based on the SERF effect, and focuses on the research progress and applications of SERF quantum precision measurement in fundamental physics, inertial navigation and biomedicine. Finally, we propose a prospect for the directions of SERF quantum precision measurement.

We demonstrate an experimental method for the in situ temperature measurement of atomic vapor using saturated absorption spectrum. By separately manipulating the frequency of pump beam and probe beam, the position of crossover peaks can move along the spectrum. Different velocity classes of atoms contribute to the crossover during the movement. We study the relationship between the intensity change of peaks and vapor temperature. Our experimental result around room temperature shows a deviation of less than 0.3 K. Compared with traditional thermometry using absorption spectroscopy, higher accuracy can theoretically be achieved for real-time thermometry.

In this paper, a hybrid algorithm to predict the wavelength drift induced by ambient temperature variation in distributed Bragg reflector semiconductor lasers is proposed. This algorithm combines the global search capability of a genetic algorithm (GA) and the supermapping ability of an extreme learning machine (ELM), which not only avoids the randomness of ELM but also improves its generalization performance. In addition, a tenfold cross-validation method is employed to determine the optimal activation function and the number of hidden layer nodes for ELM to construct the most suitable model. After applying multiple sets of test data, the results demonstrate that GA-ELM can quickly and accurately predict the wavelength drift, with an average rms error of 4.09 × 10 − 4 n m and average mean absolute percentage error of 0.21 %. This model is expected to combine the temperature and current tuning models for a wavelength in follow-up research to achieve rapid tuning and high stability of a wavelength without additional devices.