Numerical analysis of a dual-pass pumping laser with weak absorption

A model for a laser with dual-pass pumping is established, and an equation expressing the mode matching for this structure is presented. Through the numerical analysis of this equation, under the conditions of weak-absorption and effective absorption efficiency, the optimum radius of the pump beam waist as well as the optimum location is fitted to simple formulas, considering the quality of the pump beam, absorption coefficient, and beam waist of the cavity mode.Using these formulas, the laser with dual-pass pumping could be optimized to obtain a high slope efficiency. To test the utility of this model, an Nd:YVO_4 laser with dual-pass pumping and weak-absorption was built and optimized according to the results of the calculation. A good agreement between the results of the calculations and the experiment verified the model and the numerical analysis.