Experimental Investigation Of Spin Noise Spectroscopy Of Rubidium Atomic Ensemble

Spin noise spectroscopy(SNS)is a technique for detecting the spin characteristics of thermal equilibrium systems,which is originally applied to atomic ensembles.And it can reflect the spin properties,atomic energy level structure,spin's diffusion characteristics and magnetic field identification.The application of spin noise spectroscopy in semiconductor materials,quantum wells and quantum dots to study spin mechanics process and the development of spintronics devices are expected to promote spin to become the next generation of basic quantum information unit and realize storage technology beyond Moore's law.The signal-to-noise ratio(SNR)is very weak due to the detection characteristics of spin noise spectroscopy undisturbed.This thesis is based on the natural rubidium atomic cell containing 10 Torr neon(Ne)and 20 Torr helium(He)to obtain,characterize and measure the atomic information of the weak rubidium atomic ensemble spin noise signal,and analyze the influence of experimental parameters.It provides the basic experimental techniques and experience for the study of spin dynamics of other alkali metals and semiconductors,especially the effect of buffer gas on the spin of alkali atoms.It is also helpful for the development of rubidium atom spin noise spectrometer and rubidium atom magnetometer.Characteristic works including:The design and principle of spin noise spectroscopy experimental system of rubidium atomic ensemble are introduced in detail.The dependence of the spin noise power spectrum density,separately,on the probe beam's intensity,the probe beam's frequency detuning and rubidium atomic number density are studied.The spin-noise spectroscopy signal is proportional to the square of the probe beam's intensity,and the intensity also widens the half-height full width of the spectrum.Due to the uniform broadening effect of the buffer gas on the rubidium ensemble,the amplitude of the spin noise spectrum with respect to the frequency detuning of the detected light shows an"M"shape.The spin noise signal is proportional to the 1/2 power of the rubidium atomic number density.Based on the same rubidium atomic vapor cell,the influence of probe beam's frequency and rubidium atomic number density on optical magnetic resonance spectrum was studied.The SNR of rubidium D1 line ground state F_g=2 is much better than that of ground state F_g=3.The higher the rubidium atom number density,the greater the magneto-optical resonance spectrum signal.