Temperature dependence of multiphonon absorption in zinc selenide

Area of Science:

• Materials Science
• Solid State Physics
• Optical Materials

Background:

• Understanding optical absorption in materials like zinc selenide is crucial for laser applications.
• Surface and bulk absorption mechanisms can significantly impact material performance at elevated temperatures.

Purpose of the Study:

• To measure and analyze the bulk and surface absorption coefficients of zinc selenide.
• To investigate the temperature dependence of these absorption characteristics.
• To elucidate the underlying physical mechanisms contributing to optical absorption.

Main Methods:

• Laser calorimetry at 10.6 microm wavelength.
• Measurements conducted across a temperature range of 200°C to 300°C.

Main Results:

• Surface absorption revealed the disappearance of one species above 120°C and activation of another (0.13 eV) above 200°C.
• Bulk absorption increased monotonically with temperature, deviating from multiphonon theory predictions.
• Deviations were attributed to temperature-independent extrinsic absorption and a 960 cm⁻¹ absorption peak.

Conclusions:

• The study provides detailed insights into the temperature-dependent absorption of zinc selenide.
• Observed phenomena suggest complex surface interactions and bulk absorption processes.
• Findings contribute to the understanding of optical loss mechanisms in infrared optical materials.