A. V. Sidorin

Measuring nonlinear reflectance of laser radiation with a wavelength of 2940 nm from silica glass – water and silica glass – ethanol interfaces

We have measured the reflectance of an Er3+ : YAG laser pulse from silica glass – water and silica glass – ethanol interfaces at high (0.9 J cm-2) and low (5 mJ cm-2) energy densities of incident radiation. The nonlinearity of reflectance dynamics is found for high-power radiation during the laser pulse action.

Adequacy of a theoretical model in the solution of the inverse problem of the statistics of laser breakdown

An analysis is made of the possible reasons for the inadequacy of a theoretical model used to solve the inverse problem in the statistics of laser breakdown, i.e., the model employed to find the characteristics of microdefects in a given material from the statistical relationships governing laser breakdown. Some tests for checking the agreement between the model and the experimental situation are discussed. Attention is drawn to the existence of two different approaches to a statistical description of laser damage and the conditions are found under which the results of the two approaches are in agreement. A detailed analysis is made of the consequences of distortions of a laser beam wavefront. A description is given of a method for estimating the real optical strength of a material from the nature of the size dependence of laser breakdown.

Solution of the inverse problem in the statistics of laser damage to surfaces

A method is suggested for the determination of the distribution function of microdefects in respect of their thresholds of initiation of laser breakdown at surfaces. It is shown that a uniform distribution of the radiation intensity in an illuminated spot makes it possible to simplify greatly the solution of the inverse problem compared with the case of bulk damage.

Problem of accurate intensity measurements in focused laser beams

The problem of intensity measurements in sharply focused Gaussian laser beams is discussed. It is shown that existing methods have many disadvantages, particularly for small caustics. A new method is proposed for measuring the aberrations of focusing lens systems and determining the maximum intensity in a caustic.