Saturated-absorption spectroscopy: eliminating crossover resonances by use of copropagating beams.
We demonstrate a new technique for saturated-absorption spectroscopy by use of copropagating beams that does not have the problem of crossover resonances. The pump beam is locked to a transition, and its absorption signal is monitored while the probe beam is scanned. As the probe comes into resonance with another transition, the pump absorption is reduced and the signal shows a Doppler-free dip. We use this technique to measure hyperfine intervals in the D2 line of 85Rb with a precision of 70 kHz and to resolve hyperfine levels in the D2 line of 39K that are less than 10 MHz apart.
Deportment of Physics, Indian Institute of Science, Bangalore, 560 012, India.
Ayan
A
Banerjee
Vasant
V
Natarajan