$$ n = 1.48, T = 20^$$įinally, since the light passes through the rod twice, the total wavelength shift is just double the net change above. How many fringes cross the field of view each

The light source has a wavelength λ=589nm, and the rod initially is at T = 20.0☌. A Michelson interferometer has this glass rod in one arm, and the rod is being heated so that its temperature increases at a rate of 5.00☌/min. At 20.0☌ the length of the glass is 3.00cm. for analysis of thermal expansion by digital holographic interferometry.

The coefficient of linear expansion of the glass is 5.22 × 10-6/☌. approach based phase estimation in digital holographic interferometry and. 'The index of refraction of a glass rod is 1.48 at T = 20.0☌ and varies linearly with temperature, with a coefficient of 2.50 × 10-5/☌. This system is compliant with JIS R3251-1995, Measuring method of the linear thermal expansion coefficient for low expansion glass by laser interferometry. I'm probably just approaching this wrong, I'm at a loss for ideas though. This paper focuses on the progress made towards that end, which has resulted in the ability to non-destructively measure peak to valley CTE variations to within 57 parts per trillion per degree Kelvin (ppt/K) at possible spatial resolutions in the micron range on thick or thin samples.So I've been working on this question for a while and am still no further at finding an answer. ASTM D696 This test method covers determination of the coefficient of linear thermal expansion for plastic materials having coefficients of expansion greater than 1 µm/(m. However, refinement of the correlation was necessary. Corning has previously introduced the idea of measuring CTE in ULE (registered trademark) Glass using Phase Measuring Interferometry (PMI) by discovering the correlation between refractive index and CTE in ULE (registered trademark) Glass. Until now, no practical metrology technique existed that could accurately verify if a material met such requirements due to the lack of precision. Due to the unique environment required for EUVL technology, EUVL optics (and photomasks) require extremely uniform CTE properties, with targeted variations of less than 1ppb/K. The experiment results indicated that the method can avoid the measurement error induced by translation and has the potential to eliminate the measurement error induced by rotation using the rotational angle. Corning has focused its recent efforts on coefficient of thermal expansion (CTE) metrology improvements. A robust interferometric testing setup was established using a distance measuring set and two plane lenses.

Interferometry for thermal expansion