Ultra-bright source of polarization-entangled photons
US6424665B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 14, 2000 |
| Grant date | Jul 23, 2002 |
| Priority date | — |
| Expiry date | Apr 14, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S3/1083
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Utilizing the process of spontaneous parametric down-conversion in a novel crystal geometry, a source of polarization-entangled photon pairs has been provided that is more than ten times brighter, per unit of pump power, than previous sources, with another factor of 30 to 75 expected to be readily achievable. A high level of entanglement between photons emitted over a relatively large collection angle, and over a 10-nm bandwidth, is a characteristic of the invention. As a demonstration of the source capabilities, a 242-&sgr; violation of Bell's inequalities was attained in fewer than three minutes, and near-perfect photon correlations were achieved when the collection efficiency was reduced. In addition, both the degree of entanglement, and the purity of the state are readily tunable. The polarization entangled photon source can be utilized as a light source for the practice of quantum cryptography.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.