A5103126283- Spectroscopy and Laser Applications
- Superconducting and THz Device Technology
- Atmospheric Ozone and Climate
- Terahertz technology and applications
- Photonic and Optical Devices
- Semiconductor Lasers and Optical Devices
- Thin-Film Transistor Technologies
- Physics of Superconductivity and Magnetism
- Advanced Fiber Laser Technologies
- Fluid Dynamics and Thin Films
- Optical Coatings and Gratings
- solar cell performance optimization
- Atmospheric and Environmental Gas Dynamics
- CCD and CMOS Imaging Sensors
- Gyrotron and Vacuum Electronics Research
- Nanomaterials and Printing Technologies
- Silicon Nanostructures and Photoluminescence
- Nanowire Synthesis and Applications
Massachusetts Institute of Technology
2017-2023
University of Toronto
2014-2018
Room temperature operation of terahertz quantum cascade lasers (THz QCLs) has been a long-pursued goal to realize compact semiconductor THz sources. In this paper, we report on improving the maximum operating QCLs ∼ 261 K as step toward realization goal.
We report on the fabrication of 15-nm Ag films with 0.6 nm RMS roughness and only 3 times bulk electrical resistivity using a transparent AlN seed layer Ar/N2 (60% N2) based sputtering Ag. Either AlN-seeding or alone reduces percolation threshold thin smoothens their surface. However, significant reduction in localized surface plasmon resonance was observed through use sputtering. As demonstration its application as conductive film, we construct heat-regulating metallo-dielectric coating our...
GUSTO will be a NASA balloon borne terahertz observatory to launched from Antarctica in late 2021 for flight duration of 100-170 days. It aims at reviewing the life cycle interstellar medium our galaxy by simultaneously mapping three brightest cooling lines: [OI] 4.7 THz, [CII] 1.9 and [NII] 1.4 THz; along 124 degrees galactic plane through part Large Magellanic Cloud. use arrays 4x2 mixers based on NbN hot electron bolometers (HEBs), which are currently most sensitive high resolution...
We use the wave optical approach to optimize front surface inverted pyramidal grating texture on 2 400 μm thick crystalline silicon in order derive maximum photocurrent density from cell. identify a "one size fits all" periodicity of 1000 nm for c-Si absorbing layer configured with back reflector that maximizes absorption normally incident AM1.5g solar spectrum irrespective thickness. With identification such universal texture, common texturing process can be developed high-efficiency...
Room temperature operation of Terahertz Quantum Cascade Lasers (THz QCLs) has been a long-pursued goal to realize compact semiconductor THz sources. The progress toward high-temperature in QCLs relatively slow compared infrared owing more significant challenges at frequencies. Recently, the maximum operating was improved 250 K, and achievement revitalized hope community pursuit higher operations. In this paper, we report on further improvement ~261 K (-12 0C) by judiciously optimizing key...
In this paper, we simulate a front surface inverted pyramidal grating texture on 2 to 400 micron thick silicon and optimize it derive maximum photocurrent density from the cell. We identify one size fits all period of 1000 nm that leads photo-absorption normally incident AM1.5g solar spectrum in (configured with back reflector) irrespective thickness crystalline absorbing layer. With identification such universally optimized periodicity for case an texture, common fabrication process can be...
Generating multiple local oscillator beams is one challenge to develop large heterodyne receiver arrays (~100 pixels), which allow astronomical instrumentations mapping more area within limited space mission lifetime. Here, We combine a reflective Fourier grating with an unidirectional antenna coupled 3rd-order distributed feedback (DFB) quantum cascade laser (QCL) generate 81 at 3.86 THz. have measured the beam pattern of diffracted beams, agrees well simulated result from COMSOL...
Large heterodyne receiver arrays (∼100 pixel) allow astronomical instrumentations mapping more area within limited space mission lifetime. One challenge is to generate multiple local oscillator (LO) beams. Here, We succeeded in generating 81 beams at 3.86 THz by combining a reflective, metallic Fourier grating with an unidirectional antenna coupled 3rd-order distributed feedback (DFB) quantum cascade laser (QCL). have measured the diffracted scanning single pyroelectric detector plane, which...
GUSTO (Galactic/ Extragalactic ULDB Spectroscopic Terahertz Observatory) equipped with three 8-pixel detection channels at 1.4, 1.9, and 4.7 THz will perform the largest single-flight mapping of important lines nitrogen [NII], carbon [CII], oxygen [OI] respectively, within Milky Way Large Magellanic Cloud.. Whilst cutting edge technologies are applied in mixer local oscillator (LO) components, their proper coupling is crucial. Here we present design, manufacturing measurement results a...