Laser light beam noise reducing apparatus
US4672192A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 10, 1985 |
| Grant date | Jun 9, 1987 |
| Priority date | — |
| Expiry date | Jul 10, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S2301/02
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Laser beam noise reducing apparatus includes an acoustooptic cell which receives a noisy input laser light beam and produces an undiffracted or zero-order light beam and a diffracted beam in response to an RF signal at a predetermined frequency. The zero-order beam is applied to a utilization device which produces an information modulated output beam at an image zone. The zero-order beam at the output of the acoustooptic cell is sampled and AC and DC component signals are produced which are functions of fast and slow time varying changes, respectively, in the intensity of the zero-order beam. The output beam from the utilization device is sampled when it is unmodulated and a DC reference signal which represents the intensity of the DC component at the image zone is produced. The AC and DC component signals and the reference signal are combined and used to control the amplitude of the RF signal to reduce noise in the beam at the image zone.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.