Devices and methods for coherent detection using chirped laser pulses
US10067055B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 11, 2017 |
| Grant date | Sep 4, 2018 |
| Priority date | — |
| Expiry date | May 11, 2037 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/0697
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
We present here systems and methods for generating a heterodyne signal using the naturally occurring chirp of a pulsed single-mode laser. The electrical square-wave pulse used to drive the laser heats the laser cavity, causing the laser frequency to change or chirp during the emission of the optical pulse. This chirped optical pulse can be split into a chirped signal pulse that interacts with a sample and a chirped reference pulse that interferes with the chirped signal pulse on a detector to produce a heterodyne modulation whose instantaneous phase and amplitude depend on the sample's dispersion and absorption, respectively. The chirp is reproducible, so the heterodyne modulation, instantaneous phase, and/or instantaneous amplitude can be average over many measurements, either with multiple pulses from the same laser or multiple pulses from different lasers, each emitting at a different wavelength.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.