| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact optical low pass filter which is manufactured easily and easily positioned to an optical system. SOLUTION: This optical low pass filter 1 comprises a glass substrate 10, a matrix 14, and a sheet-type refractive index modulation type phase grating 12 which has a different refractive index from the matrix and has a plurality of columnar structures 16 arranged in the matrix like a grating so as to extend in the thickness direction. The glass substrate and the refractive index modulation type phase grating are joined so that the glass substrate contacts one end side of the plurality of columnar structures of the refractive index modulation type phase grating. COPYRIGHT: (C)2009,JPO&INPIT
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