Uncooled Terahertz Camera for Imaging beyond Infrared
The aim of the research program is to develop highly sensitive, uncooled, real time terahertz (THz) camera with multispectral capability using micro-electro-mechanical-system (MEMS) bi-material technology.
Imaging with terahertz (THz) radiation is attractive for security and medical applications due to its ability to penetrate most dry, non-metallic, non-polar materials without damaging them while resolving details that could be concealed in another spectral range, such as skin features and metallic objects.
The lack of appreciable THz radiation in the thermal background requires the detection using external illumination using a THz source. The imaging can be done by absorbing the incident THz radiation on the sensor pixels.
This is achieved by either using nanoscale metal films broadband detection or metamaterials for narrowband/ multispectral imaging. A MEMS bi-material sensor array was developed by integrating metamaterial absorber tuned to THZ-QCL illuminator. Potential applications include detection of concealed objects.
Fabricated sensor array and image of 3.8 THz laser beam
SCR based circuit for ionizing radiation detection
The objective of the research is to explore a novel solid-state radiation detector that operates similarly to a conventional spark chamber where the high internal gain amplifies weak signals generated by ionizing radiation.
The key advantage of the detector is that its internal gain produces a large signal compared to conventional solid-state radiation detectors that require additional support circuitry to recover the weak signals generated.
The detector can be built using standard microelectronics technology which enables high radiation hardness and the potential for detector arrays with enhanced detection and tracking capabilities. The preliminary work showed that the detector was able to detect alpha particles from a radiation source. Potential applications include detection of nuclear material.
Detection of alpha particles from a radiation source
Fly’s Ear Bio-inspired MEMS Directional Sound Sensor
The research program focuses on development of an acoustic direction finding (DF) system for localizing sound sources based on the ears of the fly Ormia ochracea.
The female of this species seek out chirping crickets to lay their eggs on, and do so with an accuracy of less than 2 degrees. The two eardrums of the fly are separated by a fraction of the sound wavelength yet it homes in on the cricket chirping with remarkable precession.
The fly employs a unique coupled mechanical bar system to extract the direction of sound with ears separated only about 500 micrometer.
The resonant excitation employed in the fly’s detection system enhances the S/N compared to omni-directional microphones used in current DF systems. This translates into enhanced direction finding accuracy.
A micro-electro-mechanical-systems (MEMS) based sensor was developed with direction sensing accuracy close to that of the fly. Potential applications include localization of sound sources.
Fabricated bio-inspired MEMS acoustic sensor and its directional respond to incident sound
- Finite element modeling of THz sensor characteristics
- Analytical and numerical modeling of metamaterial structures
- Design of metamaterial sensors
- Characterization of THz sensors
- Design and characterization of optical readout for THz sensors
- THz Image processing