Time-resolved, dual heterodyne phase collection transient grating spectroscopy

The application of optical heterodyne detection for transient grating spectroscopy (TGS) using a fixed, binary phase mask often relies on taking the difference between signals captured at multiple heterodyne phases. To date, this has been accomplished by manually controlling the heterodyne phase bet...

Full description

Bibliographic Details
Main Authors: Dennett, Cody Andrew, Short, Michael P
Other Authors: Massachusetts Institute of Technology. Department of Materials Science and Engineering
Format: Article
Language:en_US
Published: American Institute of Physics (AIP) 2017
Online Access:http://hdl.handle.net/1721.1/109513
https://orcid.org/0000-0003-2989-9550
https://orcid.org/0000-0002-9216-2482
Description
Summary:The application of optical heterodyne detection for transient grating spectroscopy (TGS) using a fixed, binary phase mask often relies on taking the difference between signals captured at multiple heterodyne phases. To date, this has been accomplished by manually controlling the heterodyne phase between measurements with an optical flat. In this letter, an optical configuration is presented which allows for collection of TGS measurements at two heterodyne phases concurrently through the use of two independently phase controlled interrogation paths. This arrangement allows for complete, heterodyne amplified TGS measurements to be made in a manner not constrained by a mechanical actuation time. Measurements are instead constrained only by the desired signal-to-noise ratio. A temporal resolution of between 1 and 10 s, demonstrated here on single crystal metallic samples, will allow TGS experiments to be used as an in-situ, time-resolved monitoring technique for many material processing applications.