Simultaneous Control of Spectral And Directional Emissivity with Gradient Epsilon‐Near‐Zero InAs Photonic Structures
Abstract
Controlling both the spectral bandwidth and directionality of emitted thermal radiation is a fundamental challenge in contemporary photonics. Recent work has shown that materials with a spatial gradient in the frequency range of their epsilon‐near‐zero (ENZ) response can support broad spectrum directionality in their emissivity, enabling high total radiance to specific angles of incidence. However, this capability is limited spectrally and directionally by the availability of materials with phonon‐polariton resonances over long‐wave infrared wavelengths. Here, an approach is designed and experimentally demonstrated using doped III–V semiconductors that can simultaneously tailor spectral peak, bandwidth, and directionality of infrared emissivity. InAs‐based gradient ENZ photonic structures that exhibit broadband directional emission with varying spectral bandwidths and directional ranges as a function of their doping concentration profile and thickness are epitaxially grown and characterized. Due to its easy‐to‐fabricate geometry, it is believed that this approach provides a versatile photonic platform to dynamically control broadband spectral and directional emissivity for a range of emerging applications in heat transfer and infrared sensing.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 09, 2023
- Source ID
- 10.1002/adma.202302956
Entities
People
- Aaswath Raman
- Jae S. Hwang
- Jin Xu
Organizations
- Defense Advanced Research Projects Agency
- National Science Foundation
- University of California, Los Angeles