A high-stability laser-pumped Cs gas-cell frequency standard

A laser-pumped Cs gas-cell type atomic frequency standard with small sensitivity to the light power and cell temperature was developed by using a Cs gas cell with precise adjustment of buffer gases. Since its light power shift coefficient of microwave frequency is nearly zero when the light frequency of the laser is at one of the saturated-absorption lines of Cs, this atomic frequency standard is a relatively simple system without an optical offset-lock system. The light frequency of the laser is stabilized in turnkey fashion. This atomic frequency standard has unique stability compared to various commercially available atomic frequency standards. It's stability is between the hydrogen maser and passive atomic frequency standards such as conventional lamp-pumped Rb gas-cell type and Cs beam type with a magnetic state selector in a measured averaging time range, from 4 sec to 1/spl times/10/sup 4/ sec, reaching a flicker floor of 2.5/spl times/10/sup -14/ at 1000 sec.