Extreme THz Science with Ultra-Intense Laser Induced Plasma

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The region of THz frequency band (0.3 – 10 THz) has long been considered the last remaining scientific gap in the electromagnetic spectrum. This field shows great promise for a variety of reasons including small-scale electron accelerators, contact-less probes, high-field nonlinear optics, and broadband material characterization. Since the use of short-pulse laser excitation on the photoconductors and the electro-optic crystals in late 1980s’, the research of THz science and technology has been limited to the marginal power level of available lasers with nano-Joule to mJ laser pulse energy. The project is basic scientific exploration, applied device innovation, and a pilot test for the extreme THz science with ultra-intense laser pulses. Greater than kJ laser pulse energy with less than 1 ps laser pulse duration for the THz science is not available anywhere in the world. PI’s preliminary experiment in the Laboratory for Laser Energetics used a multi-terawatt laser (10 J pulse energy and 1 ps pulse duration) and the Omega-EP laser (200 J pulse energy and sub-ps pulse duration) to create micro-plasma and measured THz wave generation under different laser condition during the pilot test. PI will investigate extreme THz science with THz wave generation and detection by using unique lasers (from J to kJ pulse energy). The proposed ultra-intense THz source will open the doors for a large variety of light-matter interaction applications.PI proposes to explore extreme THz wave science with the application of the most intense lasers ( kJ pulse energy and ps pulse duration) originally constructed for laser fusion at the Laboratory for Laser Energetics, Univ. of Rochester. The goal is to achieve the most intense THz sources in the world, and study nonlinear sciences with single cycle THz pulses. Single-shot spatiotemporal THz emission measurement would be the first critical development for the ultra-intense THz photonics. Proposed tasks including study of THz wave generation from different target materials (including elements with different atomic numbers as well as organic materials), pulsed laser parameters (pulse duration, laser wavelength, optical polarization, and power density), and spectral/temporally resolved measurement. The development of a single-shot THz characterization technology is imperative for the ultra-intense lasers (waiting time between the laser shot is often at 40 minutes or longer), which will also be demonstrated in our lab. Our development of the THz photonics project enables interdisciplinary research and advances numerous THz wave sensing and spectroscopy developments. If this is successful, this high-risk study may lead to new understanding, inventions, and processes with broad scientific impact. As the pursuit of progress in THz science involves extensive interdisciplinary research, this project will continue to provide excellent collaborative opportunities in the promotion of teaching, training, and learning among students with diverse socioeconomic backgrounds and within underrepresented groups. The research team will have one PhD student from an underrepresented minority group.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.