Parameter Optimization And Related Module Design Of M_z Optically Pumped Atomic Magnetometer

Mz optically pumped atomic magnetometer is used to detect the magnitude of weak magnetic fields,and it has the characteristics of high sensitivity,low power consumption and chip scale feasibility.It is widely used in mineral exploration,navigation,military antisubmarine and other fields.This paper focuses on the design and research of the Mz optically pumped atomic magnetometer.The work is mainly divided into the following aspects:First,we conduct experimental study on the parameters of the physical system of Mz magnetometer,which includes laser power and radio frequency(RF)field intensity,and we obtain the law curve of the ratio of amplitude and line width of the magnetic resonance signal.By analyzing the curve characteristics we determine the optimal parameter value,which provides a reference for the implement of the magnetometer prototype.In addition,we analyze the characteristics of various system noise in the physical system and electronics system of the magnetometer,in which FM-AM noise and shot noise are the main noises that affect the sensitivity of the magnetometer.Second,in order to provide a standard uniform magnetic field in the sensitivity calibration of the magnetometer,we explore the magnetic field uniformity of the coils of different structure types.Through simulation we find that the magnetic field uniformity of the four-segment Barker coils in the magnetic field space(?)6cm×5cm is better than 0.001%,which is much higher than that of the circular Helmholtz coils.This simulation provides a reference for the selection of pattern and size of the three-dimensional standard magnetic field coil.According to the requirement for the uniformity of RF magnetic field in the atomic vapor cell and the structure of the physical system in the magnetometer probe,we use circular Helmholtz coil to design the RF coil's structure and size.Third,we design and optimize the heating temperature control system for the atomic vapor cell of the magnetometer.The the high-frequency electric heating method is used in the heating circuit,with the structure of twisted pair heating wire,which effectively reduce the magnetic field interference generated by the heating current;The high-resolution 24-bit ADS1211 chip is selected to collect the bridge voltage in the temperature acquisition circuit.In terms of software algorithm,the increment PID is used to control the temperature.The temperature controlling accuracy of the implemented temperature control system reaches 12mK,which is of great significance for improving the sensitivity of the magnetometer.