Methods of and apparatus for measuring picosecond semiconductor laser pulse duration using the internally generated second harmonic emission accompanying the laser output
US4772118A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 14, 1986 |
| Grant date | Sep 20, 1988 |
| Priority date | — |
| Expiry date | Jul 14, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J11/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The duration of a very short semiconductor laser pulse, such as that ranging from a fraction to hundreds to picoseconds, can be measured utilizing the internally generated second harmonic emission of the laser. A laser diode is driven so that light emitted therefrom can pass through a beam splitter and be reflected by the beam-splitter into a photomultiplier and into a detector, respectively. Signals received therefrom relate to the conversion efficiency of the second harmonic emission generated by the picosecond pulses and of either continuous wave emission or pulse emission whose durations can be accurately measured by photodetectors. Apparatus includes a photodiode for measuring the fundamental laser power, a photomultiplier for measuring the second harmonic power, and appropriate filters. Ammeters coupled to the photodiode and photomultiplier measure the appropriate current. The ratio of the current can be determined by a ratio circuit or a computer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.