Ultra-short pulse generation from mid-IR to THz range using plasma wakes and relativistic ionization fronts
Open Access
- 1 February 2021
- journal article
- research article
- Published by AIP Publishing in Physics of Plasmas
- Vol. 28 (2), 023106
- https://doi.org/10.1063/5.0039301
Abstract
This paper discusses numerical and experimental results on frequency downshifting and upshifting of a 10 μm infrared (IR) laser to cover the entire wavelength (frequency) range from λ = 1 to 150 μm (ν = 300–2 THz) using two different plasma techniques. The first plasma technique utilizes frequency downshifting of the drive laser pulse in a nonlinear plasma wake. Based on this technique, we have proposed and demonstrated that in a tailored plasma structure, multi-millijoule energy, single-cycle, long-wavelength IR (3–20 μm) pulses can be generated by using an 810 nm Ti:sapphire drive laser. Here, we extend this idea to the THz frequency regime. We show that sub-joule, terawatts, single-cycle terahertz (2–12 THz or 150–25 μm) pulses can be generated by replacing the drive laser with a picosecond 10 μm CO2 laser and a different shaped plasma structure. The second plasma technique employs frequency upshifting by colliding a CO2 laser with a rather sharp relativistic ionization front created by ionization of a gas in less than half cycle (17 fs) of the CO2 laser. Even though the electrons in the ionization front carry no energy, the frequency of the CO2 laser can be upshifted due to the relativistic Doppler effect as the CO2 laser pulse enters the front. The wavelength can be tuned from 1 to 10 μm by simply changing the electron density of the front. While the upshifted light with m propagates in the forward direction, that with m is back-reflected. These two plasma techniques seem extremely promising for covering the entire molecular fingerprint region.
Keywords
Funding Information
- National Science Foundation (1734315)
- Air Force Office of Scientific Research (FA9550-16-1-0139)
- U.S. Department of Energy (DE-SC0010064)
- Office of Naval Research (MURI (N00014-17-1-2075))
This publication has 62 references indexed in Scilit:
- Imaging ultrafast molecular dynamics with laser-induced electron diffractionNature, 2012
- Studies of spectral modification and limitations of the modified paraxial equation in laser wakefield simulationsPhysics of Plasmas, 2012
- Nonlinear Theory for Relativistic Plasma Wakefields in the Blowout RegimePhysical Review Letters, 2006
- Observation of Laser-Pulse Shortening in Nonlinear Plasma WavesPhysical Review Letters, 2005
- The physics of the nonlinear optics of plasmas at relativistic intensities for short-pulse lasersIEEE Journal of Quantum Electronics, 1997
- Generation of tunable radiation using an underdense ionization frontPhysical Review A, 1991
- Frequency shifts induced in laser pulses by plasma wavesPhysical Review A, 1990
- Nonlinear theory of intense laser-plasma interactionsPhysical Review Letters, 1990
- Nonlinear interaction of intense laser pulses in plasmasPhysical Review A, 1990
- Photon acceleratorPhysical Review Letters, 1989