Stress-optic coefficients of ZnSe.

Prior research has established that stress-optic coefficients are essential for understanding how materials respond to mechanical stress in optical applications. However, limited data exists for specific materials like ZnSe, particularly under controlled experimental conditions. It was already known that ZnSe is used in optical systems due to its transparency in the infrared range. No prior work had resolved the precise stress-optic coefficients of ZnSe using interferometric techniques. This gap motivated the need for precise measurements to support optical design and material modeling. Existing methods lacked the accuracy required for high-precision applications. The lack of detailed coefficients hindered the development of ZnSe-based optical components. This study aimed to address these limitations by employing advanced interferometric methods.

The aim of this study was to determine the stress-optic coefficients of ZnSe with high precision at room temperature. The researchers focused on measuring pi(11) and pi(12) to support optical and mechanical modeling. The motivation arose from the need for accurate material properties in optical engineering applications. The study sought to improve upon previous methods by using interferometric techniques. The problem addressed was the lack of precise experimental values for ZnSe. This uncertainty limited the material's use in high-precision optical systems. The study aimed to provide a reliable dataset for future design and analysis. The goal was to achieve sub-fringe accuracy in coefficient measurements.

The study used Twyman-Green and Fizeau interferometers to measure stress-optic coefficients. A four-point loading device was employed to apply controlled stress to ZnSe specimens. Test samples were rectangular parallelepipeds of chemically vapor-deposited ZnSe. The optical propagation direction was aligned with the deposition axis. Fringe positions were determined using optical scanning and computer analysis. The setup allowed for measurements with an accuracy better than 0.01 fringe spacing. The method ensured minimal interference from external variables. The combination of interferometry and controlled loading enabled precise coefficient determination.

The experimental value for pi(11) was found to be -1.48 ± 0.05 × 10⁻¹² m²/N. The value for pi(12) was measured as +0.22 ± 0.05 × 10⁻¹² m²/N. These results represent the first high-accuracy measurements of ZnSe stress-optic coefficients. The Twyman-Green and Fizeau interferometers provided consistent data. The four-point loading device ensured uniform stress application. Optical scanning allowed precise fringe detection. Computer analysis improved measurement accuracy beyond prior methods. The results suggest ZnSe exhibits anisotropic stress-optic behavior.

The authors report that ZnSe has distinct stress-optic coefficients pi(11) and pi(12) at room temperature. The measured values suggest anisotropic optical behavior in ZnSe. The study confirms that interferometric methods can yield precise stress-optic data. The results provide a reference for optical design involving ZnSe components. The coefficients align with theoretical expectations for similar materials. The accuracy achieved supports use in high-precision optical systems. The authors propose that these values may guide future material modeling. The findings may also inform the development of ZnSe-based optical devices.