Mid-infrared metamaterial intersubband polariton emitters
The goal of the project is to develop mid-infrared optical sources by engineering the quantum mechanical interaction between light and semiconductor quantum wells in metamaterials with designer photonic environments. Many molecules of interest interact strongly with mid-infrared light (3-30 Ã¬m) and these new sources will enable sensing and imaging for applications in industry, medicine, and homeland security. The program combines quantum and photonic engineering to design fundamentally new sources with improved emission efficiency. Special quantum states that are simultaneously light and matter are incorporated into metamaterials with engineered photonic environments. Both the quantum state and the photonic environment are designed to emit photons at an increased rate. In addition to advancing the state-of-the-art for mid-infrared emitters, this program also seeks to address education and diversity in science, technology, engineering, and mathematics by engaging local students in outreach events that focus on understanding the role of light and optics in consumer technologies.
The program aims to improve the radiative quantum efficiency of incoherent mid-infrared sources by engineering ultra-strong coupling between the photon field in a metamaterial resonator and electronic intersubband transitions in semiconductor quantum wells. The overall theme of the proposal is to improve the emission rate of photons using quantum and photonic engineering rather than incremental improvements to devices such as quantum cascade lasers. Several innovations to increase the light-matter coupling strength are proposed, such as using InP-based materials and excited state intersubband transitions. Another innovation is the incorporation of hyperbolic metamaterials into the resonator design to enhance the photonic density of states, thus further improving spontaneous emission. The approach for the program is integrated, including, theoretical, computational, design, fabrication, and experimental efforts to (1) develop mid-infrared metamaterial resonators, (2) increase light-matter coupling strength, and (3) implement efficient electrical injection mid-infrared emitters. Designed metamaterials with quantum wells will be grown via molecular beam epitaxy and fabricated into devices in a state-of-the-art nanofabrication facility. The materials and devices will be characterized using Fourier transform infrared spectroscopy. The work in this program will develop a basis for incorporating metamaterials into active optoelectronic devices and also lay a foundation for engineering ultra-strong light-matter coupling in electrically pumped devices. The goals of this program are ambitious: incoherent mid-infrared sources with more than 3 mW of power and greater than 0.5% conversion efficiency superseding alternative approaches such as sub-threshold laser emission that is four to five orders of magnitude less efficient.