EAGER: A New Class of Room Temperature THz Detectors and Spectrometers

University Of Arizona, Tucson AZ

Investigators

Abstract

Terahertz radiations are gaining significant interest in a wide range of applications including communication, medical diagnostic, defense and non-invasive identification of chemicals and biological compounds. One of the unique properties of terahertz radiation is the ability to pass through a range of materials, thus making it possible to "see through" many packaging materials such as paper, plastics, and wood. Despite significant progress in the field, terahertz detectors still have major limitations in speed, detection frequencies and operating temperature. The aim of this EAGER proposal is to develop a novel, potentially disruptive method through nonlinear frequency conversion for the detection of far-infrared and terahertz radiations. The research will provide theoretical and experimental foundations for design and development of high-speed, room temperature integrated terahertz receivers with significant societal impact. The broader impact of the research focuses on the education and training of graduate and undergraduate students in both theoretical and experimental areas of optoelectronic research. The research will broaden participation of women and underrepresented minorities through internship and summer REU programs. Terahertz waves, with a frequency range of 0.1/10 THz are nonionizing radiations with significant advantage in non-invasive detection and identification. The aim of this EAGER research is to create a fundamental understanding of a novel, potentially disruptive approach for the detection of far-IR and THz radiation over a broad spectral range. The design is based on cavity-enhanced unbalanced frequency mixing of the terahertz signal with a single-mode laser pump, nonlinear frequency conversion via sum frequency generation through a periodically-poled lithium niobate (PPLN) nonlinear crystal. The result is the generation of a new output signal in the optical frequency having the signature of the terahertz radiation that will be efficiently detected using widely available high speed, low-noise silicon or InGaAs PIN detectors. The intellectual merits of this high-risk high-reward exploratory research is the development of a new class of efficient, CMOS-compatible receivers and spectrometers in the hard-to-detect frequencies. The research effort will include detailed modeling combined with experimental validation of frequency and power conversion as well as sensitivity and noise evaluation. The findings provide new knowledge and findings at the intersection of electronics, optics and photonics, and hybrid integration. 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.