| 摘要 |
PURPOSE:To obtain high resolution even in spectral measurement which requires high-wavelength resolution by providing a non-reflective coating to at least >=1 window surfaces of an optical window and reducing noises due to optical interference. CONSTITUTION:When the absorption spectrum of a sample is measured through the optical window A, reflected light P2 reflected by a window surface (a) of the optical window A is generated in addition to specific transmitted light P1. Here, the transmitted light P1 and reflected light P2 are shown by P1=P0XT2 and P2=P0XR1XR2XT2, where P0 is incident light, R1, the reflection factor of the window surface (a) of the optical window A, R2 the reflection factor of a window surface (b), and T2 the transmissivity of the window surface (b). Here, when the nonreflective coating is provided to the window surface (a) of the optical window A, the reflection factors R1 and R2 decrease, and consequently the reflected light P2 is reduced to suppress interference. Consequently, noises due to light interference are reduce the obtain the high accuracy even in the spectral measurement which requires the high-wavelength resolution. |
