OPTIMUM PUMPING POWER FOR OPTICALLY PUMPED FIR LASERS.

Summary form only given. The relations between the output power of optically an pumped FIR laser and the pumping power were studied theoretically by solving the density matrix equation of a four-level system by means of the matrix signal flow graph method. The output power density of the FIR laser was calculated by the iterative method. A set of curves of output FIR laser power density against pumping power has been obtained. It is found that every curve has a maximum point whose position varies with the pumping detuning. On the basis of these results, an optimum power density is predicted for an optically pumped FIR laser with certain pumping detuning. The results should be applicable to the design of optically pumped FIR lasers.