Light beam intensity controlling apparatus
US4629879A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 1984 |
| Grant date | Dec 16, 1986 |
| Priority date | — |
| Expiry date | Jun 11, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/113
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Beam intensity controlling device includes an acoustooptic cell which receives an input 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. An error signal is produced which is a function of the differences in the intensity of the zero-order beam from a desired level. This error signal is used to control the amplitude of the RF signal which in turn changes the intensity in the diffracted and zero-order beams such that the zero-order beam intensity is maintained relatively constant and can be provided as an input to a modulating device. The error signal has two components, a DC component which corrects for slow drift of the zero-order light beam intensity and an AC component which corrects for higher frequency changes in the zero-order light beam intensity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.