Exposure of a Transparent Material with a Laser Radiation Band Gap with a Wavelength from the Spectral Region of the Absorption Edge
This work is a fundamental study of the process of motion of the heating region towards laser radiation during laser pulsed modification of the transparent materials structure. Numerical estimates of the magnitude of thermomechanical stresses in the material (2–3 GPa) are given. This significantly exceeds the elastic limit of semiconductor materials (40–100 MPa). A mechanism for the formation of linear tracks of microcracks directed from the focusing region of the laser pulse to the surface of the material is proposed. As a result, the effect of blocking the temperature rise in the focal region arises during the remaining pulse duration.
The choice of the energy and time parameters of the laser pulse, the geometrical position of the focus makes it possible to implement two types of changes in the material structure: spot or extensional. An experimental confirmation of this possibility has been obtained for monocrystalline semiconducting zinc selenide. Both types of structural changes can be used to solve a wide range of practical problems.
Tags: material heating by laser radiation monocrystalline semiconductor zinc selenide multiphoton absorption optical breakdown thermomechanical stresses ultrashort pulse lasers лазеры с ультракороткими импульсами многофотонное поглощение монокристаллический полупроводниковый селенид цинка нагрев материала лазерным излучением оптический пробой термомеханические напряжения
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