Green to blue light conversion through resonant four wave mixing in rubidium vapor

This work experimentally demonstrates the conversion of coherent and incoherent green 532 nm light to collimated blue 420 nm light through resonant four-wave mixing in rubidium vapor. The 532 nm light co-propagates with 795 nm and 1320 nm CW pump beams, simultaneously taking advantage of resonances between the 5 P, 10 S, 6 P and 5 S ground states of rubidium. Using a coherent green beam, the intensity of the collimated 420 nm signal is characterized under varying polarizations, cell temperatures, frequency detunings and pump intensities. A 2 d image is up-converted from green to blue light to extend the technique to spatially incoherent light. This excitation pathway has the potential to be used as a narrow linewidth ( < 1 GHz), tunable bandpass filter for lidar or other remote sensing applications. • Narrow linewidth of 532 nm signal up-converted to blue light using four wave mixing. • Demonstration of image up-conversion using hot Rb vapor. • A third applied IR pump beam increases conversion efficiency.