Use of time characteristics of laser emission in the determination of the optical density and absorption nonlinearity of matter

An internal resonator method is suggested for the determination of the optical density and absorption nonlinearity of matter. The method is based on the change in the Q factor of the resonator due to introduction of an absorbing medium and on the corresponding changes in the rise time and repetition period of laser pulses. Expressions are derived for the calculation of the optical density and absorption nonlinearity. The results are given of a ruby laser investigation of solutions of phototropic substances and of a model plasma with a high concentration of sodium.