Infrared detectors and imagers can provide night vision, object detection and tracking, measure spectral and thermal signatures, and more. Coverage across the infrared allow you to “see” things that are not possible in the visible or other spectral regions. Infrared capabilities are critical for defense and security, industrial processes and diagnostics, biological and medical imaging, and science applications such as astronomy and quantum optics. There is a continual need to develop infrared detector technologies with improved signal-to-noise ratio and detector operability in imaging arrays while minimizing the size, weight, and power (SWaP) of systems. We explore new materials and quantum heterostructures that could provide fundamental performance advantages over existing materials or to cover shortcomings in spectral detection. Our work on novel materials includes exploration of InAs/GaAs quantum dot intersubband detectors, InGaBiAs alloys on InP, InGaAs/GaAsSb type-II superlattices on InP, and ultra-low-doped HgCdTe. We develop new detector architectures that can provide low noise, reduced temperature requirements, or to facilitate integration of multiple spectral windows on a single detector platform. These include Auger-suppressed device architectures and barrier-integrated HgCdTe detectors.

Spectral shaping and filtering of infrared light is a critical need for spectroscopy and imaging. We study microscale filters based on dielectric gratings that could provide dramatic reductions in system size and new functionality through locally defined spectral response in arrays. These dielectric gratings are based on guided mode resonance in high index contrast structures with periodicity near the optical wavelength, providing unique optical behavior through photonic bandstructure engineering that can result in broadband reflection, focusing, and narrowband reflection. We are investigating fundamentals of these dielectric grating filters and their application in the mid-wave infrared (MWIR, 3-5 microns) and long-wave infrared (LWIR, 8-12 microns) spectral region.

Wirelessly interconnected systems are becoming pervasive today, forming the Internet of Things. These autonomous devices and systems continue to scale to reduced dimensions at the millimeter scale to micrometer scale, with applications ranging from safety and security to healthcare. The continued scaling of these systems opens new avenues in bridging the physical world with the cyber world. Optoelectronic devices provide highly scalable means of efficient wireless power transfer, high throughput and low energy data communication, and a broad array of optical sensing capabilities. We explore photovoltaic energy harvesting to self-power microsystems using light sources including solar, artificial room lighting, and infrared transmission through biological tissue. Our devices and energy harvesting systems have been used on the Michigan Micro Mote for applications including microscale imagers, biological studies on Monarch butterfly migration, and bio-implantable systems. We are further developing integrated optoelectronics to provide power and data communications capabilities for wireless neural sensor arrays. Such neural sensor arrays would provide a path for reliable brain-computer interfaces to answer fundamental neuroscience questions and to overcome physical limitations such as loss of motor function.