Absorption coefficients in highly transparent solids: barothermal theory for cylindrical configurations

Area of Science:

• Materials Science
• Optical Engineering
• Laser Physics

Background:

• Accurate measurement of low absorption coefficients is essential for developing highly transparent solids.
• Existing methods may lack sensitivity for detecting very low absorption at laser wavelengths.
• Understanding heat transfer dynamics is key to novel measurement techniques.

Purpose of the Study:

• To propose and theoretically evaluate a novel method for measuring very low absorption coefficients in solids at laser wavelengths.
• To investigate the feasibility of using gas pressure changes as an indicator of solid absorption.
• To model the thermal and pressure responses in a solid-gas system subjected to laser irradiation.

Main Methods:

• Numerical calculation of temperature profiles within a weakly absorbing solid.
• Simulation of temperature and pressure profiles in a confined, nonabsorbing surrounding gas.
• Analysis of heat transfer from the laser-heated solid to the gas medium.

Main Results:

• Calculations demonstrate significant heat transfer from the solid to the surrounding gas.
• The heat transfer is predicted to cause a measurable pressure increase in the gas.
• This pressure rise correlates with the absorption coefficient of the solid.

Conclusions:

• A novel, non-contact method for measuring low absorption coefficients in transparent solids is proposed.
• The proposed method leverages laser-induced thermal expansion and gas pressure changes.
• This technique offers a promising approach for quality control and material characterization in optical applications.