A snapshot of our newly renovated, laboratory addition. Here, we will develop new tools for evanescent-wave cavity ring-down spectroscopy (EW-CRDS). Such devices allow CRDS measurements of condensed matter.

The laboratory facilities behind the pillar use CRD and REMPI spectroscopies to measure reaction rate coefficients and other properties of free radicals.

Other NIST Links

Cavity Ring-down Spectroscopy within the Experimental Chemical Kinetics & Thermodynamics Group at NIST

Jeffrey W. Hudgens
Robert E. Huie

From this page you can review our research that employs CRDS methods:

  1. Experimental studies that use CRDS to measure gas-phase reaction rate coefficients.

  2. Development of CRDS methods for studies of surfaces, thin films, and condensed matter in general:

    • Novel EW-CRDS experiments that probe condensed matter with evanescent waves.

    • Design and optimization of ring mini-cavity devices for EW-CRDS.

 

Measurements of Gas-Phase Reaction Rate Constants

We are using CRDS to improve the quality of kinetic data and to measure chemical kinetics under reaction conditions that were previously inaccessible to study.

Diagram of the basic ring-down experiment. We use this method to measure reaction rate coefficients.

Background about Apparatus:

Recent CRDS Studies:

Evanescent Wave Cavity Ring-down Spectroscopy in Condensed Phase Media

This project has two elements:

  • The design and construction of devices that extend CRDS technology to condensed matter.

  • Application of novel CRDS and EW-CRDS devices to the study of chemical reactions at interfaces.


Background of EW-CRDS:
Diagram of a square, total-internal-reflection ring mini-cavity. This device uses CRDS to measure the attenuation of evanescent waves by surface absorbed species or by thin films. Photon tunneling introduces light into the cavity and extracts a small portion for monitoring. Piezoelectric translators precisely control the input and output coupling efficiency. Our square prototype recently exhibited a 1/e decay time of ~800 nsec.
Publications on Ring Resonator Development:
This Page is maintained by Jeff Hudgens: <Hudgens@nist.gov>
Updated on 4 Aug 1999.