Near-field optical apparatus with a laser having a non-uniform emission face
US5625617A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 6, 1995 |
| Grant date | Apr 29, 1997 |
| Priority date | — |
| Expiry date | Sep 6, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S2301/18
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Near-field optical apparatus according to the invention contains a novel semiconductor laser photon source. The source is capable of providing substantially higher photon flux than prior art near field sources, potentially facilitating read-out rates in the megahertz range in exemplary near-field data storage and retrieval apparatus. The novel source comprises a non-uniform laser emission face, with the emission face configured such that at least 50% of the total radiation emission is from a small (first) region of the emission face, of width less than .lambda..sub.s /2, where .lambda..sub.s is the emission wavelength of the laser. In an exemplary embodiment, a multilayer coating is provided on the emission face, such that radiation emission from the face is relatively low. A recess is formed in the coating such that substantial radiation emission from the recess occurs. The recess constitutes the first region. Exemplarily, the coating comprises at least one dielectric layer, with at least one conductor layer thereon. The recess extends through the conductor layer, and exemplarily is formed by FIB (focussed ion beam) etching. A variety of other embodiments are also disclosed, as ar…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.