SYNCHRONOUSLY PUMPED LASER WITHOUT INVERSION IN CADMIUM

We report a lasing without inversion (LWI) experiment on the basis of coherent population trapping, realized in low-pressure cadmium vapor. A single-pass inversionless amplification by more than a factor of 10 has been measured, a significant improvement over previous experiments . In addition, we report synchronously pumped laser oscillation withou t inversion. Using a simple model to fit the gain/absorption curves as a function of magnetic field, we have obtained values for the populat ions in the system, showing that there is no inversion in the atomic b asis. Combined with a simple optical method to measure absolute densit ies of a gas, this model results in a completely optical method to det ermine the absolute populations and density in the system.