Electronically Tunable Terahertz Electronically Tunable Terahertz Detector Using Plasmons Plasmons Detector Using Jess Crossno Physics Santa Barbara City College Mentor: Greg Dyer Research Advisor: Dr. Jim Allen Undergraduate Researchers: Sean Haney, Bill Sowerwine In Partnership with:
Why the need for THz research? Why the need for THz research? Technology Gap: Gap between Electronics and Photonics. Electronics fail to produce adequate power above several hundred GHz Photonics fail to produce adequate power below several THz *THz = Terahertz = 1 Trillion Cycles per second
THz Applications THz Applications � Technology applications Current technology � Information operates at ~1-10GHz � Ultra fast signal processing or ~1-10 billion bits per � Massive data transmission second � Environment � Atmospheric sensing � Defense Terahertz frequencies � Chemical/Biological agent operate at ~1-10 THz detection or ~1-10 trillion bits per � Digital radar second � Imaging � Covert communication Millimeter-wave radar images taken � Space-space 9 km from a nuclear power plant can detect when the plant is � Short range battle field operating (upper image) � Unknown applications created or idling (lower image). by new technology http://www.thznetwork.org www.thznetwork.org http://
Final Goals � Goals: � Research and develop terahertz electronics (300 GHz – 10 THz) � Objectives: � Nanoelectronics for THz sources and detectors. � Detectors � Tunable detectors for THz using plasmonic resonance � Sources � THz Bloch oscillator.
Resonant Frequency Plasmon frequency dependence ∝ 2 f n p Electron Density
Resonant Frequency Plasmon frequency dependence ∝ 2 f n p
The Split- -Grating Gate Detector Grating Gate Detector The Split Grating gates Finger Source Gate Source Drain 4uM 4uM |---- ----| | | Grating gates 1mm AlGaAs GaAs Finger Gate Drain FET
Future Work � Continue to chart device’s behavior � Determine optimized settings: � Source/Drain Current � Wiring � Temperature � Frequency Range � Implement device into applications
Acknowledgments • The Allen Group: • Sandia National Labs: • Dr. Eric Shaner • Dr. Jim Allen • Dr. Mark Lee • Greg Dyer • Dr. Mike Wanke • Dr. Thomas Feil • Dr. John Reno • Dr. Alex Kozhanov • Sean Haney • INSET: • Bill Sowerwine • Samantha Freeman • Dr. Nick Arnold • CUNY: • Liu-Yen Kramer • Greg Aizin • Luke Bawazer • Dr. Evelyn Hu
Extra slides Extra slides
Current Research Current Research V o lta g e R e sp o n s e G a te V o lta g e -5 0 0 m V C u rre n t 1 0 u A 0 .0 0 5 0 .0 0 0 -0 .0 0 5 Voltage (V) -0 .0 1 0 -0 .0 1 5 -0 .0 2 0 -0 .0 2 5 -0 .0 3 0 -8 .0 µ -6 .0 µ -4 .0 µ -2 .0 µ 0 .0 2 .0 µ 4 .0 µ 6 .0 µ 8 .0 µ 1 0 .0 µ T im e b a se (s)
Current Research Current Research Signal response and relax tim e vs current FEL .48 THz FEL .48 THz Vg: -500 m V, 20 K 0.4 1E-4 Signal Response (Unitless) 0.2 Relaxation time (s) 0.0 1E-5 -0.2 -0.4 1E-6 -0.6 -0.8 -70 -60 -50 -40 -30 -20 -10 0 10 20 Current (uA)
Wiring Diagram for Split- -Grating Gate Grating Gate Wiring Diagram for Split Detector Detector Polarization
S D Diagram
Why Image in THZ? Why Image in THZ? 0.6 THz image Can see through visibly opaque objects THz has no or minimal health risk Can use passive detection (QinetiQ, UK, US)
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