1 Distribution A: Approved for public release; distribution is unlimited
Integrity Service Excellence
Adaptive
Multimode
Sensing
Date: 07 03 2013
Jim Hwang Program Officer
AFOSR/RTD Air Force Research Laboratory
2 Distribution A: Approved for public release; distribution is unlimited
2013 AFOSR SPRING REVIEW 3001B PORTFOLIO OVERVIEW
NAME: Jim Hwang BRIEF DESCRIPTION OF PORTFOLIO: Adaptive Multimode Sensing LIST SUB-AREAS IN PORTFOLIO:
I. Adaptive Multimode Sensing – Emphasize tunable detectors and different detection modes such as polarization and phase (in addition to intensity and color). Main challenge: phase detection.
II. Novel Infrared Sensors – Emphasize novel materials and structures such as quantum dots, nano-wires, type-II superlattices, and 3D integration. Main challenge: dark current.
III.Solar Cells, Thermoelectric Coolers & Others – Deemphasize to focus portfolio with reducing budget.
3 Distribution A: Approved for public release; distribution is unlimited
Motivation Shorten time from sense to kill; avoid drowning in data
4 Distribution A: Approved for public release; distribution is unlimited
-2 V
S.I. GaAs Substrate
LWIR AlGaAs/GaAs QWIP
NIR AlGaAs/GaAs PIN
-2 V
S.I. GaAs Substrate
LWIR AlGaAs/GaAs QWIP
NIR AlGaAs/GaAs PIN
Near IR LWIR
77 K
3-Color detector demonstrated, too.
Optically-Switched 2-Color Infrared Detector Yong-Hang Zhang (Arizona State) & Elizabeth Steenbergen (AFRL/RXAN)
5 Distribution A: Approved for public release; distribution is unlimited
Speed/Sensitivity Trade-Off of IR Detectors Vladimir Mitin (Buffalo) & Andrei Sergeev (Buffalo)
Potential barriers around charged InAs quantum dots
(QDs) in GaAs prevents recombination and
prolongs electron lifetime
Charged QDs strongly enhance IR response of
photo-detectors/solar cells
p+ GaAs InAs QDs n+ GaAs
InAs QDs n+ GaAs
n+ GaAs
6 Distribution A: Approved for public release; distribution is unlimited
Electrically Switchable Plasmonic Polarizers Xuejun Lu (Mass-Lowell)
Field distribution (resonance wavelength) can be switched by electrically biasing the polarizer
Rec
tang
ular
Arr
ay o
f A
u Pl
asm
onic
Pol
ariz
ers
7 Distribution A: Approved for public release; distribution is unlimited
Spectral-Polarization Imaging Viktor Gruev (Washington, St. Louis)
Color Filters Angle of Polarization Image
SEM of Al Nanowires
Si
Si Cone
Polarization Filter
8 Distribution A: Approved for public release; distribution is unlimited
0 100 200 300 400 500 600 700
0.0
0.1
0.2
0.3
0.4
Pho
tocu
rren
t (µA
)
Time (ns)
x0.3PbS QD
2 nm
(111) planes
(111) planes
0.004 0.006 0.008 0.010 0.012 0.0141E-5
1E-4
1E-3
0.01
0.1250 167 125 100 83 71
1E-1
QD
Dec
ay R
ate
(ns-1
)
1E-2
T (K)
1/T ( K-1)
Non-radiative Energy Transfer
Si
Non-radiative Energy Transfer from Quantum Dots
Anupam Madhukar (S. Cal.), M. Mahalingam (RXAN) & G. Brown (RXAN)
Controlled energy/charge transfer between colloidal nanostructures and conventional semiconductors
Substrate
QD
10−1
10−2
10−3
10−4
10−5 Pho
tolu
min
esce
nce
Dec
ay (/
ns)
Si
9 Distribution A: Approved for public release; distribution is unlimited
Crystalline Bismuth Nanowire Jimmy Xu (Brown)
Bi Pt
Bi Pt
IR/THz Detector
• Bi: only known natural negative index material @ 60um or 5THz
• Bi oxides easily • 1st Bi/Pt heterojunction
successfully grown
10 Distribution A: Approved for public release; distribution is unlimited
InAs/GaSb Type II Superlattices Sanjay Krishna (New Mexico), Vincent Cowan (RVSS), Christian Morath (RVSS) & John Hubbs (RVSS)
Collaboration with Raytheon Vision Systems
• Type II superlattices with antimonides barriers can compete with HgCdTe for infrared sensing
• Strong interests from AFRL (RX, RY, RV), Army NVL, MDA and DARPA
• Enhanced multimodal functionality (color, polarization, dynamic range, phase) through integration with metamaterials
Mid-IR Response @ 420 K!
GaSb
InAs
EC
EV
11 Distribution A: Approved for public release; distribution is unlimited
Single-Crystal Semimetal/Semiconductor Nano-Composites
Chris Palmstrøm (UCSB) & Kurt Eyink (AFRL/RXAN)
Incr
easi
ng E
rSb
com
posi
tion
[001
] ρ˔ ρ//
{110}
GaSb
ErSb
GaSb
ErSb
GaSb (ErSb)x(GaSb)1-x (Semimetal) (Semiconductor)
•ErSb/GaSb nano-composites grown by molecular beam epitaxy
•Buried conductive layers for multicolor infrared detectors
•THz polarizers embedded in III-V heterostructures
12 Distribution A: Approved for public release; distribution is unlimited
Funding Trend
I. Adaptive Multimode Sensing – Emphasize tunable detectors and different detection modes such as polarization and phase (in addition to intensity and color). Main challenge: phase detection.
II. Novel Infrared Sensors – Emphasize novel materials and structures such as quantum dots, nano-wires, type-II superlattices, and 3D integration. Main challenge: dark current.
III.Solar Cells, Thermoelectric Coolers & Others – Deemphasize to focus portfolio with reducing budget.
