A sensor system comprises a laser source that emits a pump beam at a first wavelength and a probe beam at a second wavelength, and an optical means for receiving the pump and probe beams. The optical means is operative to generate a plurality of light beams, each having a different frequency, from the pump and probe beams. One or more cells receive the light beams from the optical means and allow passage of the light beams therethrough, with the cells containing alkali atoms. A dichroic filter is configured to receive the light beams from the cells. The dichroic filter separates pump beam light and probe beam light from the light beams. A detector array receives the probe beam light from the dichroic filter. The detector array includes a two-dimensional array of photosensors that map out transmission of respective light beams corresponding to the probe beam light through the cells.