Abstract
In Na vapor, amplified spontaneous emission (ASE) and parametric four-wave mixing (FWM) involving two-photon resonant 3s yields 4d transitions and near-resonant stimulated Raman (SR) down to 4p states were studied. Conversion efficiencies for IR and UV generation through and near the 4p levels were measured over a wide range of Na density and pump laser intensity to reveal a process which eventually limits IR and UV generation. It has been suggested that pump absorption and three-photon ionization limit conversion efficiencies for the parametric FWM process. If SR and parametric FWM are ignored, the two-photon resonant ionization yield through Na 4d can be easily calculated to be approximately 70%/atom for 3-mJ laser pulses at 10 MW/cm**2. With the number of atoms in the laser beam larger than the number of laser photons, only approximately 18% beam depletion was observed at 4s-3d resonance, indicating that ionization is suppressed and, therefore, not primarily responsible for gain saturation. At 2-Torr Na and pump intensity of 13 MW/cm**2, power conversion efficiencies have been measured for the UV and IR. These and other results are described.
Original language | English |
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Title of host publication | Unknown Host Publication Title |
Publisher | Optical Soc of America |
Pages | 74-75 |
Number of pages | 2 |
ISBN (Print) | 0936659513 |
State | Published - 1987 |