skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • Home
  • Search Results
  • Page 1 of 1

Search for: All records

Award ID contains: 2308946

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. ; ; ; (, Plasma Sources Science and Technology)
    Abstract We report on the development of a highly sensitive electric field induced second harmonic generation diagnostic setup capable of measuring electric field strengths as low as 1 V cm − 1 at the picosecond time scale under atmospheric pressure conditions. This unprecedented sensitivity is achieved through passive homodyne detection, which utilizes stray signals generated by an optical component in the beam path. Our detection limit of 0.3–0.5 V cm − 1 represents an improvement of over 2–3 orders of magnitude compared to previous reports (100–1000 V cm − 1 ) in the literature. Additionally, we demonstrate sensitivity to the polarity of the electric field. Experimental results are corroborated by simulations of the 400 ps time-resolved homodyne process, offering deeper insights into the enhanced detection capabilities and the system’s ability to resolve the field sign. 
    more » « less
  2. ; ; ; (, Optics Letters)
    We report on the experimental observation of non-resonant, second-order optical sum-frequency generation (SFG) in five different atomic and molecular gases. The measured signal is attributed to a SFG process by characterizing its intensity scaling and its polarization behavior. We show that the electric quadrupole mechanism cannot explain the observed trends and suggest a mechanism based on symmetry breaking along the incident beam path arising from laser-induced species ground state number density gradients. Our results demonstrate that the SFG is about four orders of magnitude stronger than the third-harmonic generation (THG) and independent from any externally applied electric fields. These features make this method suitable for gas number density measurements at the picosecond time scale in reactive flows and plasmas. 
    more » « less