DIFFRACTION GRATING ELEMENT

• Main Authors: SHIOZAKI MANABU, MOBARA MASAICHI
• Format: Patent
• Language: English
• Published: 20.08.2009
• Subjects: OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS

PROBLEM TO BE SOLVED: To provide a diffraction grating element capable of improving the diffraction efficiency and reducing polarization dependence of the diffraction efficiency in a wide wavelength band. SOLUTION: In a diffraction grating element 30, a first medium 31 is provided outside a first plane P1and in contact with a first plane P1. A second medium 32 and a third medium 33 are alternately provided in a predetermined direction parallel to the first plane P1to form a diffraction grating between a second plane P2and a third plane P3, in contact with the second plane P2and the third plane P3. A fourth medium 34 is provided outside the third plane P3and in contact with the third plane P3. A fifth medium 35 is provided between the first plane P1and the second plane P2, in contact with the first plane P1and the second plane P2. When an average refractive index between the second plane and the third plane is represented by nav, an average refractive index n5of the fifth medium satisfies a relational expression of n1<n5<navor nav<n5<n1. COPYRIGHT: (C)2009,JPO&INPIT