Spatial encoding of a laser beam by means of a Stark cell modulator
US4215324A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 1, 1978 |
| Grant date | Jul 29, 1980 |
| Priority date | — |
| Expiry date | Aug 1, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/174
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Apparatus for coding a laser beam to provide guidance signals, or the like. In the transmitter, the laser beam traverses two modulators to provide two-dimensional encoding. In the receiver, the detected signals are amplified, frequency-discriminated, and mixed to form guidance signals. The modulator is a modified Stark cell wherein four split longitudinal planar electrodes allow for beam encloding as a function of two frequencies by the process of molecular absorption. Bias and modulating signals applied to the electrodes interact with the molecular absorbing gas and with the beam to encode position information as a function of the specific frequencies. The amplitude of the first encoding frequency varies from a maximum at one edge of the beam, decreasing to a minimum at the opposite edge, and vice versa for the second encoding frequency. The amplitudes of both are equal on beam center. A second embodiment utilizes a pair of internal bias electrodes and four external electrodes to apply bias and modulating signals. The modulator wall is thin for penetration of the modulating signals so as to interact with the beam. A third embodiment utilizes four semicircular disc electrodes trans…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.