Experimental Study Of Raman Lasers For Cold Atom Interference

Atom interferometers have a wide range of applications in precision measurement fields such as gravity acceleration,gravity gradient,gyroscopes,fine structure constants,and Newton's gravitational constants.In addition,in the verification of basic physics theory,such as verifying the equivalent principle,detecting gravitational waves,atom interferometers are also being used more and more in this field.In the field of gravity acceleration measurement,the fountain-type Raman type 87Rb atom interferometer is used by most atom interferometer research units in the world.The Raman lasers pulse technique and its phase noise research are even indispensable for the study of interaction with atoms.The Raman lasers prepared by optical injection locking in this paper can be used for atom interferometer.However,the phase of atom interference fringes is greatly affected by phase noise of Raman lasers.For this reason,we have experimentally studied the phase noise under different experimental conditions of the master laser.Experimentally,two phase-locked Raman lasers with a frequency difference of 6.834 GHz are obtained by optical fiber EOM(Electro-Optic Modulator)modulation and injection locking.In the experimental system,the master laser is modulated by 6.834 GHz fiber EOM and output as seed light.By adjusting the slave laser,the first amplification of output beam of-1 level's frequency is implemented.The result shows that the beat line width of Raman lasers is not wider than 1 Hz,the frequency is adjustable to 300 MHz,the phase noise is less than-60 dBc/Hz from 10 Hz to 100 kHz when master laser is frequency-locked and the Raman lasers phase noise of master laser frequency under different scanning ranges is also studied.On this basis,we also used the prepared Raman lasers pulse to interact with 87Rb atoms to measure the Raman transition spectrum,Rabbi oscillation and Ramsey fringes in the same-direction Raman configuration,and discuss the results.