Researchers from the Changchun Institute of Optics, Fine Mechanics and Physics developed an improved Fizeau interferometry method to enhance the precision of measuring the coefficient of thermal expansion (CTE) in fused quartz. The study provides a more reliable approach for characterizing ultra-low expansion materials used in high-end optical and semiconductor systems. The research results were published in Measurement.

The coefficient of thermal expansion is a key parameter that describes how materials change in size with temperature. In advanced technologies such as extreme ultraviolet lithography and precision optics, even nanometer-scale deformation can significantly affect system performance. Conventional measurement methods, including mechanical dilatometers and sensor-based techniques, often face limitations due to contact errors, environmental disturbances, or insufficient resolution when measuring ultra-stable materials.

To address these challenges, the research team developed a refined interferometry-based measurement strategy. Instead of relying on physical contact, the method used light interference to detect extremely small changes in length as temperature varied. By introducing a reference structure and optimizing how phase signals were analyzed, the researchers reduced common sources of measurement uncertainty and improved overall stability.

A key improvement of the method lies in its enhanced measurement reliability. Traditional interferometric techniques can suffer from phase ambiguity and sensitivity to external noise. In this work, the researchers adopted an optimized measurement approach that allowed more consistent tracking of phase changes, ensuring that thermal expansion could be accurately determined over a practical temperature range.

Experimental results demonstrated that the method achieved high precision and repeatability in measuring the thermal expansion of fused quartz. Compared with conventional approaches, it produced more stable results and effectively minimized interference from environmental factors such as temperature fluctuations and vibrations. The achieved accuracy meets the requirements for evaluating ultra-low expansion materials in demanding engineering applications.

Beyond improving measurement performance, the study highlights the broader importance of precision metrology in modern technology. Accurate characterization of thermal expansion supports the design of more stable optical systems and improves manufacturing precision in semiconductor processes. It is also critical for applications such as space-based instruments and high-precision sensing, where thermal stability directly impacts reliability.

This work provides a practical and scalable solution for high-precision CTE measurement. By improving both accuracy and robustness, the method offers valuable support for the development of next-generation technologies that depend on strict thermal control.