| 摘要 |
PROBLEM TO BE SOLVED: To provide optical parts that have wavelength selectivity for transmitting desired light and eliminating unnecessary light, and can be laid on the bottom surface of an element such as PD. SOLUTION: The optical parts are composed of a light transmission substrate, and a wavelength selection layer that has a band gap wavelength λg1 being shorter than a wavelength λ2 of light to be transmitted and at the same time being longer than a wavelength λ1 of light to be eliminated and is formed on one surface or both the surfaces of the substrate. |
