Quantum Limited Atomic Resonance Optical Filter.

The first demonstration of an atomic resonance optical filter based upon Rb vapor is presented. Diode lasers have been used for the first time to pump an atomic resonance optical filter. This represents a significant technical advance since simple, reliable, and efficient diode lasers make the laser-pumped atomic resonance optical filter practical outside the laboratory environment. Also, a diode laser frequency stabilization system was designed and built for this work. This system is capable of stabilizing the frequency of diode laser up to 2.7 {rm KHz}_{rm p-p}. The measured signal to noise ratio of the diode laser-pumped atomic resonance optical filter based upon Rb vapor is 38.4 dB. However, the sidelight fluorescence was so strong that it could be seen by human eyes. The full width at half maximum of the detection bandwidth is measured to be 1.18 GHz at the Rb cell temperature of 150 ^circC, which shows a good agreement with the calculated detection bandwidth of 1.02 GHz. The quantum efficiency of this atomic resonance optical filter was measured to be linearly dependent on the diode laser pump power. An analysis of the potential noise sources of a Rb vapor atomic resonance optical filter system has been presented. The dominant noise source in this experiment is calculated to be the collisions between Rb(5p) atoms.