General Abstract: The objective of this research effort is to develop optical materials and devices that control and emit far-infrared (far-IR) light with wavelengths between 20-60microns. There are a number of important applications for light in this wavelength range, ranging from imaging for astronomy and cosmology efforts and sensing of aromatic hydrocarbons, asphaltenes, and biological materials. However, the far-IR is an extremely challenging wavelength range to work in, with little to no optical infrastructure for either conducting fundamental research or developing optical devices and systems, making the far-IR arguably one of the few remaining frontiers of the electromagnetic spectrum. The challenges of the far-IR largely stem from the lattice vibrations (phonons) of most of the semiconductors used for optoelectronic devices across the electromagnetic spectrum. In the far-IR, phonons strongly absorb light and conventional device designs are no longer appropriate. In this program we will look to harness these lattice vibrations and utilize them to generate electromagnetic radiation, or light. In doing so, we will develop an architecture for engineering designer far-IR materials and emitters that incorporate unique light-matter interactions in an oft-neglected portion of the optical spectrum, resulting in an optical toolkit for the far-IR and a new generation of optical devices. At the same time, we will undertake both educational and outreach efforts, as well as a coherent effort to grow the visibility and impact of far-IR optoelectronics research, which has no agreed-upon dissemination systems (journals, conferences, workshops), commercial vendors, or even nomenclature.
Technological developments over the past several decades have significantly increased our ability to generate, control, and detect electromagnetic (EM) radiation across an ever-increasing range of wavelengths. Much of this progress has been spurred by the rapid growth of semiconductor optoelectronic technologies. Yet the far-infrared (far-IR, 20-60 ìm) wavelength range has not shared in this explosive growth. Ironically, a primary reason for the lack of progress in the far-IR lies in the semiconductor crystal lattice itself: characteristic vibrations of the lattice, known as phonons, interact strongly with far-IR light and result in strong optical absorption. This program aims to explore and develop a set of technologies, materials, and phenomena which will serve as the technical foundation of an optical infrastructure for the largely undeveloped far-IR wavelength range. In particular, we propose to develop optical materials and opto-phononic-electronic (OPE) devices that control and emit far-IR light by engineering electronic transport, surface waves, and the interaction of these surface waves with bulk optical phonons. In doing so, we will develop an architecture for engineering designer far-IR materials and OPE emitters that incorporate unique light-matter interactions in an oft-neglected portion of the optical spectrum, resulting in an optical toolkit for the far-IR and a new generation of optical devices. Concurrent with the technical thrusts of the proposed effort, we will: i) bring STEM-based activities into K12 classrooms and after-school programs and ii) work to cultivate an intellectual community with a shared interest in the far-IR by means of virtual communities and special issues in peer-reviewed publications.
