Calorimeter to Measure the 10.6-microm Absorption of Metal Substrate Mirrors

Area of Science:

• Optical Engineering
• Materials Science
• Laser Technology

Background:

• High reflectivity mirrors are crucial for laser systems.
• Accurate measurement of optical absorption is essential for performance optimization.
• Existing methods for measuring mirror absorption have limitations.

Purpose of the Study:

• To design, construct, and test a novel calorimetric instrument for measuring 10.6-micrometer absorption in high reflectivity metal-substrate mirrors.
• To establish a precise and accurate method for quantifying optical absorption.
• To provide extensive absorption data for state-of-the-art mirrors.

Main Methods:

• Calorimetric measurement technique utilizing in situ heat capacities.
• Accurate measurement of reflected laser light (±4%).
• Simplified data reduction technique for efficient analysis.

Main Results:

• The developed instrument achieves an accuracy of ±0.1 alpha and a precision of 0.0005.
• Comparative measurements were performed against other reflectivity and absorption devices.
• The best measured absorption was 0.0010 for a gold-coated multidielectric enhanced mirror.

Conclusions:

• The novel calorimetric instrument provides a highly accurate and precise method for measuring optical absorption in mirrors.
• The findings offer valuable data for the development and selection of high-performance optical components.
• The instrument is suitable for characterizing state-of-the-art 10.6-micrometer mirrors.