Transcript Novel Periodic Solid State Devices for Terahertz Emission

Novel Periodic Solid State Devices for
Terahertz Emission and Detection
NIRT 0609146 : Nanostructure Components for Terahertz Spectroscopy on a Chip
Greg Dyer, Jesse. Crossno*, James. Kally*, Kavir. Dass*, S.J. Allen, Gehong Zeng, and John Bowers (UC Santa Barbara)
Peter Robrish, Rick Trutna, Dan Mars and Greg Lee (Agilent)
* Undergrad research interns
Greg Aizin (City College New York)
Eric Shaner, Mike Wanke and John Reno (Sandia)
Objectives
Voltage Controlled Lateral Barrier
DC & GHz Bias Scheme
– Terahertz Emission
– Terahertz gain in an electrically sold state device
– Room temperature operation
– Coherent radiation
– mW power
– Terahertz Detection
– Narrow-band response
– Tunability
– LN2 or higher T operation
T = 20 K
– Ring and disk metal cladded resonators
–Super-superlatice includes n+ doped layers to
mitigate electric field domain formation
Terahertz Spectroscopy
Filling the Terahertz Source Gap
– Quantum cascade lasers
(QCLs) require cryogenic
temperatures
– Barrier gate biased produces potential barrier in 2D channel
– Gate controls barrier and by diode-like activation model
– Electronics have low
output power at high THz
frequencies
Resonant Response
– Bloch
oscillator
has
potential to provide tunable
terahertz radiation at room
temperature
T = 20 K, VBG = -850 mV
–InSb or Si composite bolometer to detect emission (left)
Bloch Oscillations and the Stark Ladder
– Terahertz interferometer to analyze spectral content (right)
– Under positive bias, a
sharp resonant feature is
present
Plasmonic Terahertz Detectors
–Equivalent views: Scattering from Bragg planes (left) or
Stark ladder (right)
– Under negative bias,
appears to be double
resonance
Hot Electron Bolometric Response
‘opening’ of
T = 20 K, n = 420 GHz
–Gain without inversion
Harmonic Generation and
Parametric Gain
– Grating gate offers tunability of electron density
– Additional barrier gate
beyond pinchoff
increases
responsivity
when
biased
– Superlattices are highly non-linear materials
– DC and/or RF bias scheme for harmonic generation (left), parametric
gain (right), or LSA mode operation
Center for Terahertz Science and Technology
UC Santa Barbara
Sandia is a multiprogram laboratory
operated by Sandia Corporation, a
Lockheed Martin Company, for the
United States Department of Energy
under contract DE-AC04-94AL85000.