Influence on the Lifetime of 87Rb Bose-Einstein Condensation for Far-Detuning Single-Frequency Lasers with Different Phase Noises

摘要

We study the influence of the phase noises of far detuning single frequency lasers on the lifetime of Bose-Einstein condensation (BEC) of 87 Rb in an optical dipole trap.As a comparison,we shine a continuous-wave singlefrequency Ti:sapphire laser,an external-cavity diode laser and a phase-locked diode laser on BEC.We measure the heating and lifetime of BEC in two different hyperfine states:|F =2,mF =2〉 and |F =1,mF =1〉.Due to the narrow linewidth and small phase noise,the continuous-wave single-frequency Ti:sapphire laser has less influence on the lifetime of 87 Rb BEC than the external-cavity diode laser.To reduce the phase noise of the external-cavity diode laser,we use an optical phase-locked loop for the external-cavity diode laser to be locked on a Ti:sapphire laser.The lifetime of BEC is increased when applying the phase-locked diode laser in contrast with the external-cavity diode laser.