Polarizing diffraction element and optical head device
US7738346B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 2006 |
| Grant date | Jun 15, 2010 |
| Priority date | — |
| Expiry date | Feb 9, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03H2222/31
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A polarizing diffraction element having a wavelength selectivity which functions as a polarizing diffraction element at a wavelength λ1, and which does not function as a diffraction grating not depending on incident polarization state and shows high transmittance at a wavelength λ2, and an optical head device employing the element, are provided.The polarizing diffraction element selectively diffracts or transmits incident light having two different wavelengths each containing a first circularly polarized light and a second circularly polarized light having a rotation opposite from the rotation of the first circularly polarized light, depending on wavelength and polarization state of the incident light. Then, a reflective wavelength region for at least the first circularly incident light, does not contain said two incident wavelengths.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.