A LASER-PUMPED ULTRANARROW BANDWIDTH OPTICAL FILTER

An atomic optical filter with ultranarrow bandwidth has been developed . This filter has two operating channels generated from two hyperfine energy levels in the Cs ground state with a 9.2 GHz frequency separati on. By employing a cw Ti:sapphire laser to alternatively pump the pola rized Cs atoms to a selected hyperfine energy level, each of the two c hannels can be, respectively, used as emitting and receiving terminals . Compared to a normal Faraday anomalous dispersion optical filter, th ere is an increase in transmittance and a decrease in total equivalent bandwidth in this filter. (C) 1998 American Institute of Physics. [S0 003-6951(98)01941-X].