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 ⁵²_D5/2 other states such as ⁷²_S1/2 ⁷²_P3/2 ⁶²_P3/2 ⁶²_P1/2 and ⁵²_D3/2 have also been populated effectively. Meanwhile, multiple wavelength filters exploiting atomic transitions to these states can be realized.