Single-beam spin polarization and detection method

Abstract

The invention discloses a single-beam spin polarization and detection method. A device used in the method comprises a laser, a DMD, two linear polarizing films, two quarter-wave plates, a magnetic shielding cylinder, a temperature controller, a y-direction magnetic field coil, an atomic gas chamber and a photoelectric detector. The implementation process of the method is as follows: laser light emitted by the laser is subjected to amplitude modulation through the DMD, and the modulation frequency is Larmor precession frequency caused by a y-direction magnetic field By; after sequentially penetrating through the a first linear polarizing film and a first quarter-wave plate, the laser light becomes elliptical light and irradiates on the high-temperature atomic gas chamber; atoms in the gas chamber are polarized by utilizing circular polarization components of elliptically polarized light, and polarization of the atoms is detected by utilizing linear polarization components of the elliptically polarized light, namely, an optical rotation angle is generated; and finally, the light sequentially passes through a second quarter-wave plate and a second linear polarizing film, the light intensity is measured on the photoelectric detector, and the optical rotation angle is obtained according to a calculation model. The optical path is simple, the power consumption is low, and spin imaging and magnetic microscopic imaging are easy to realize.

Description

technical field [0001] The invention belongs to the technical field of atomic magnetometers, and in particular relates to a single-beam spin polarization and detection method. Background technique [0002] Atomic magnetometer is a method to measure the magnetic field based on the interaction between light and atoms and atoms and magnetic field. It uses the precession of atoms to realize the measurement of magnetic field. Compared with other magnetic microscopy techniques such as SQUID magnetic microscopy and diamond color center magnetic microscopy, atomic magnetometers have the highest magnetic field sensitivity, and have greater application prospects in applications with high magnetic field sensitivity. [0003] The atomic magnetometer technology realizes the spin polarization of the alkali metal atom through the circularly polarized light whose frequency corresponds to the frequency of the alkali metal D1 line. After the spin polarization, the magnetic moment of the atom ...

AI Technical Summary

Problems solved by technology

The Faraday modulation method and the photoelastic modulation method respectively use the Faraday modulator and the photoelastic modulator to modulate the detection light, and finally obtain the size of the optical rotation angle through the lock-in amplifier demodulation. The key of these two methods is the modulation and demodulation, because the measurement device needs Modulation and demodulation, which makes the optical path complex and high power consumption

The differential detection method uses a polarization beam splitter (PBS) to detect the detection light differentially. Since the optical rotation angle is small, the optical rotation angle can be approximated by the differential detection formula, but this method not only requires two photodetectors, but also the polarization Dichroic prisms also complicate the structure of the device

[0004] Conventional atomic magnetometers detect optical rotation angles through modulation and demodulation or differential detection, but these methods are difficult to achieve in terms of spin imaging. On the other hand, in many places in scientific research and production and life, simple devices and optical paths are required. The structure is compact, and the existing methods cannot meet the demand

How to realize the simplification of the measurement optical path and spin imaging is a crucial research content of the atomic magnetometer, and there are no relevant research results in this area.

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