Cs 728 nm excited state Faraday anomalous dispersion optical filter with indirect pump

We demonstrate a Cs excited state Faraday anomalous dispersion optical filter (ESFADOF) operating at 728 nm using a novel pump method, by which the pump beam and the probe beam in the ESFADOF realized here have no a common energy level. Using this method, the ESFADOF achieves a transmission of 2.39% with a bandwidth of 22.52 MHz, which can be applied to both laser frequency stabilization and future four-level active optical clocks. Under the 455 nm laser pump, in addition to 5 2 D 5 / 2 , other states such as 7 2 S 1 / 2 , 7 2 P 3 / 2 , 6 2 P 3 / 2 , 6 2 P 1 / 2 and 5 2 D 3 / 2 have also been populated effectively. Meanwhile, multiple wavelength filters exploiting atomic transitions to these states can be realized.