Laser hydrophone and virtual array of laser hydrophones
US5504719A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 19, 1974 |
| Grant date | Apr 2, 1996 |
| Priority date | — |
| Expiry date | Sep 19, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01H9/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention relates to a hydrophone and to a virtual array of hydrophones for sensing the amplitude, frequency, and in arrays, the direction of sonic waves in water. The hydrophone employs a laser beam which is focused upon a small "focal" volume of water in which natural light scattering matter is suspended and which matter vibrates in synchronism with any sonic waves present. The vibration produces a phase modulation of the scattered light which may be recovered by optical heterodyne and sensitive phase detection techniques. The sonic waves are sensed at locations displaced from the focusing lenses. Because of this remote sensing capability, the physical hardware of an array of hydrophones may be confined to a small area comparable to the dimensions of the lenses themselves while the sensing of the sonic waves virtually occurs at widely spaced, remote focal volumes. Thus, by combining the signals from these remote focal volumes, a virtual array of hydrophones may be formed whose dimensions are large enough in relation to the sonic wavelengths of interest to achieve high directionality but without the penalties of hydrodynamic drag usually associated with large area arra…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.