Characterizing passive coherent population trapping resonance in cesium vapor cell filled with neon as buffer gas

We present a pair of phase-locked lasers with a 9.2-GHz frequency difference by injection locking of a master laser to an RF-modulation sideband of a slave diode laser. Using this laser system, the coherent population trapping (CPT) signal with a typical linewidth of ～ 182 Hz is obtained in a Cs vapor cell filled with 30 Torr (4 kPa) of neon (Ne) as buffer gas. We investigate the influence of the partial pressure of Ne buffer gas on the CPT linewidth, amplitude, and frequency shift. The results may offer some references for CPT atomic clock and CPT atomic magnetometer.