Bidirectional transmittance distribution function measurements on ZnSe.

Area of Science:

• Optics and Photonics
• Materials Science
• Optical Metrology

Background:

• The bidirectional transmittance distribution function (BTDF) is crucial for characterizing light scattering in optical materials.
• Chemically vapor-deposited (CVD) zinc selenide (ZnSe) is a significant optical material, necessitating accurate scattering property evaluation.
• Existing methods for BTDF measurement face limitations due to instrumentation constraints.

Purpose of the Study:

• To develop and validate a working equation for BTDF measurements of CVD ZnSe, accounting for practical instrumentation limitations.
• To present a comprehensive dataset of BTDF for CVD ZnSe across varying thicknesses and laser wavelengths.
• To establish a standardized methodology for BTDF assessment in optical materials.

Main Methods:

• Development of a BTDF measurement equation addressing finite detector size, sample surface effects, and detector linearity.
• Detailed description of the specialized instrumentation and data collection procedures for BTDF analysis.
• Experimental setup utilizing three laser wavelengths (0.6328, 3.39, and 10.6 µm) and three ZnSe sample thicknesses (6, 19, and 25 mm).

Main Results:

• Empirical BTDF data were collected and plotted against the angle from the sample normal for CVD ZnSe at room temperature.
• Scattering characteristics were quantified for different ZnSe thicknesses and across the specified laser wavelengths.
• The developed BTDF methodology proved effective in characterizing the optical scattering behavior of the material.

Conclusions:

• The developed BTDF measurement approach provides a viable method for assessing the scattering properties of optical materials like CVD ZnSe.
• The presented data offer valuable insights into the wavelength and thickness-dependent scattering behavior of ZnSe.
• This work contributes to the precise characterization of optical components for advanced applications.