TY - GEN
T1 - Spatially Enhanced Electric Field Induced Second Harmonic (SEEFISH) Generation for Measurements of Electric Field Distributions in High-Pressure Plasmas
AU - Raskar, S.
AU - Orr, K.
AU - Adamovich, I. V.
AU - Chng, T. L.
AU - Starikovskaia, S. M.
N1 - Publisher Copyright:
© 2022, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
PY - 2022/1/1
Y1 - 2022/1/1
N2 - The spatial resolution of the ps Electric Field Induced Second Harmonic (EFISH) generation has been enhanced by using non-collinear laser beam phase matching schemes. The pump laser beam (1064 nm, nominal pulse duration 150 ps, pulse energy 20-40 mJ) is separated into two coaxial or crossing beams, overlapping only near the focal point. The Spatially Enhanced EFISH (SEEFISH) signal is generated over a shorter beam overlap region compared to the collinear phase matching. Blocking of either of the two beams results in a complete suppression of the signal. The signal is spatially isolated from the "conventional" EFISH signal and measured by a photomultiplier detector. Measurements of a known Laplacian field generated between two parallel cylinder electrodes in ambient air shows that SEEFISH improves the spatial resolution of the measurements by about a factor of 2. The spatial resolution is improved further by reducing the focal distance of the lens. The magnitude of the SEEFISH signal is significantly lower compared to that of the single-beam EFISH and decreases dramatically with the beam crossing angle, due to the phase mismatch. The new diagnostic has a significant potential for measurements of electric field distributions in high-pressure plasmas, with an additional benefit of removing the stray second harmonic signal from the optical access windows.
AB - The spatial resolution of the ps Electric Field Induced Second Harmonic (EFISH) generation has been enhanced by using non-collinear laser beam phase matching schemes. The pump laser beam (1064 nm, nominal pulse duration 150 ps, pulse energy 20-40 mJ) is separated into two coaxial or crossing beams, overlapping only near the focal point. The Spatially Enhanced EFISH (SEEFISH) signal is generated over a shorter beam overlap region compared to the collinear phase matching. Blocking of either of the two beams results in a complete suppression of the signal. The signal is spatially isolated from the "conventional" EFISH signal and measured by a photomultiplier detector. Measurements of a known Laplacian field generated between two parallel cylinder electrodes in ambient air shows that SEEFISH improves the spatial resolution of the measurements by about a factor of 2. The spatial resolution is improved further by reducing the focal distance of the lens. The magnitude of the SEEFISH signal is significantly lower compared to that of the single-beam EFISH and decreases dramatically with the beam crossing angle, due to the phase mismatch. The new diagnostic has a significant potential for measurements of electric field distributions in high-pressure plasmas, with an additional benefit of removing the stray second harmonic signal from the optical access windows.
UR - https://www.scopus.com/pages/publications/85123782675
U2 - 10.2514/6.2022-1616
DO - 10.2514/6.2022-1616
M3 - Conference contribution
AN - SCOPUS:85123782675
SN - 9781624106316
T3 - AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022
BT - AIAA SciTech Forum 2022
PB - American Institute of Aeronautics and Astronautics Inc, AIAA
T2 - AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022
Y2 - 3 January 2022 through 7 January 2022
ER -