Project Summary 1 UNCLASSIFIED UNCLASSIFIED Photonic-Crystals In Military Systems Energy Harvesting, Thermal Camouflage, & Directed Energy Leo DiDomenico 3 Hwang Lee 1 Marian Florescu 1 Irina Puscasu 2 Jonathan Dowling 1 1 Department of Physics & Astronomy, Louisiana State University 2 Ion Optics Inc. 3 Xtreme Energetics Inc. Points of Contact: Dr. Leo D. DiDomenico [email protected]& Prof. Jonathan P. Dowling [email protected]
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Project Summary 1 UNCLASSIFIED Photonic-Crystals In Military Systems Energy Harvesting, Thermal Camouflage, & Directed Energy Leo DiDomenico 3 Hwang Lee.
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Project Summary
1UNCLASSIFIED
UNCLASSIFIED
Photonic-Crystals In Military Systems
Energy Harvesting, Thermal Camouflage, & Directed Energy
Leo DiDomenico3
Hwang Lee1
Marian Florescu1
Irina Puscasu2
Jonathan Dowling1
1 Department of Physics & Astronomy, Louisiana State University
Alternating materials of higher & lower refractive indices
Periodicity: on the order of wavelength of light
Functionality: semiconductors for light
Project Summary
9
3-Dimensional Photonic Crystals
The math can be very complexbut the basic idea is VERY SIMPLE...
Scattered waves can add destructivelyfor some frequencies and from somedirections…
Therefore, certain very special PBG structures have all directions of propagation forbidden over a band of frequencies.
3D Crystal Structure with scattering plans
shown
Each scattering site contributes to the total
Wave response.
Project Summary
10
•TDOS measures the number of states {kx, ky, kz, n} that radiate.•TDOS is the number of states for a given dω about the frequency ω. •Opto-Thermal applications require extending the idea of TDOS.•The TDOS must be extended to account for the overlap of
The periodic dielectricThe Radiation field.Atoms with atomic transitions. Temperature distribution.
1D 2D
New Design Tools are Needed for Opto-Thermal Engineering with Photonic Crystals
The fields do not always overlap the dielectric whereatoms can absorb or emit energy & heat the material.
An extension of basic radiation theory, which now includes photon-phononinteractions inside a PBG material with a non-uniform temperature distribution, is being developed by the authors and with the intent of develop engineering software tools for opto-thermal PBG materials.
Project Summary
11
Photonic Crystal Fiber
Opal
Inverted Opal
Woodpile
Butterfly Wing
Silicon Pillars
Photonic Crystals:Examples
Project Summary
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A Dizzying Array ofPotential Applications
Band Gap: Semiconductors for Light
Band-Gap Shift: Optical Switching & Routing
Local Field Enhancement:Strong Nonlinear Optical Effects
Anomalous Group Velocity Dispersion:Negative index metamaterials for stealth applications and super-prism dispersion, true time delay lines
Micro-cavity Effects: Photodetectors, LED
Low-Threshold Lasers
Project Summary
13
Contents
Introduction to Applications of Photonic Band Gap (PBG) Material
What is a Photonic Band Gap Material?
Generating Electricity from Spectral & Directional Control of IR Radiation
Controlling Thermal Radiation for IR Camouflage
Pumping Laser Weapons with Thermal Radiation from PBG Materials
Initial Experimental Studies On PBG Thermal radiation control
Project Summary
14
PV Cells Need a Matched SpectrumPV Cells Need a Matched Spectrum
Heat Generated!
Out of band energy from PV cell,creates waste heat but no electricity !
TPV Cell
There are 2 potential solutions Using Photonic Crystals …
Project Summary
15Method 1: Thermal Gradients Allow
Rethermalization
Cold
Hot
Band GapLight Cone
RethermalizeOut of Band Energy
PhotonicCrystal
HeatSource
To TPV
Project Summary
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Thermal Radiation in PBG Material
RECALL:
•Spectral Intensity: position, direction, & frequency
•Absorptivity: T(r), direction, # of levels, & frequency
•Energy velocity depends on PCS
•Total density of atom-connected photon states
Photon-PhononInteraction in
Non-PBG
Now extend principles to a PBG material
Project Summary
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TPV Energy Conversion:PBG Spectral Control
SpectralFunnel
(Not a Filter)
TPV Cell Device
Broad BandHeat Source
Project Summary
18
TPV Energy ConversionState-of-the-art
• Intermediate Absorber/Emitter
• Filter: Only the photons with right energy
• Keep operating temperatures lower
• Recycle: Heat the absorber with the
unused photons
Improve conversion efficiency: Recycling the unused photons to heat the Emitter/absorber
Incorporate PBG into a Classic TPV Design
Project Summary
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⎟⎟⎠
⎞⎜⎜⎝
⎛−⎟⎟
⎠
⎞⎜⎜⎝
⎛
ΩΩ
−=As
A
S
ATPV T
T
T
T 04
4
11η
absorber cell
AΩ
SΩ
ATST
0T
Solid angle for absorber
Solid angle for the sun
Temp of the thermal source
Temp of absorber
Temp of the cell
1000 2000 3000 4000 5000 6000
0.2
0.4
0.6
0.8
85%
Full concentration π=ΩS
TA = 2500 K
Method 2: TPV Energy Conversion:Using PBG Directional Control
Instead of increasing ΩS (concentration), decrease the solid angle of the intermediate absorber, ΩA.
T Kelvin
Project Summary
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Novel PBG Angle-Selective Absorber
Novel Design of an efficient angle-selective PBG absorber
• a wave-guide channel in 2D PBG embedded in a 3D PBG structure• single-mode (uni-directional) operation for a wide range of frequency• alternative structures can be designed to achieve a prescribed efficiency• LSU patent application
• For a given blackbody input power, T= 400 K (area under the red curve)– Filter
• only eliminates lower and higher spectral components, selecting incident radiation in a narrow range
• Appreciable amount of energy is wasted– Photonic crystal
• funnels the incident energy into a narrow spectral range• runs at a higher effective temperature (defined by the blackbody with the same maximum peak power)
ProposedCurrent
20 % Transfer efficiency5 % Transfer efficiency
Project Summary
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Contents
Introduction to Applications of Photonic Band Gap (PBG) Material
What is a Photonic Band Gap Material?
Generating Electricity from Spectral & Directional Control of IR Radiation
Controlling Thermal Radiation for IR Camouflage
Pumping Laser Weapons with Thermal Radiation from PBG Materials
Initial Experimental Studies On PBG Thermal radiation control
“On demand” optical transmission and reflection spectra three characteristic length scales: radius of the cylinders, distance between the cylinders and width of the rectangular veins (optimum values: r/a=0.078, L/a=0.194 and w/a=0.38) full photonic band gap (both polarizations) of ω/ωc=18.25% centered on ωc/ω0=0.83 presents spectral regions with high reflection concomitant with a large number of modes at lower frequencies (high transmission)
Photonic crystal structure Photonic band structure
Project Summary
25
Doubly-Periodic Photonic Crystals:Dual-Band Optical Properties (II)
“On demand” field distribution depending on the frequency the field can be localized in different regions of the high-index of refraction dielectric or in the air fraction spatial field distribution can be used to optimize the coupling to absorbers placed into the structure in order to enhance thermal emission
Electromagnetic field distribution for TM modes for the first three bands at the M-point
Project Summary
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Dynamical Tuning of Spectral Emissivity
Normalized emission from photonic crystal test structure at 325 C under different gas conditions: different concentration values for CO2 and N2. (right side-zoom in)
Possibility of tuning the emissivity of the structure by gas choice and by controlling its gas concentration
Introduction to Applications of Photonic Band Gap (PBG) Material
What is a Photonic Band Gap Material?
Generating Electricity from Spectral & Directional Control of IR Radiation
Controlling Thermal Radiation for IR Camouflage
Pumping Laser Weapons with Thermal Radiation from PBG Materials
Initial Experimental Studies On PBG Thermal radiation control
Project Summary
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Energy Separation - I Energy Separation - I
Schematic of energy flow: 1. Temperature gradient moves phonons left to right & Rethermalizes.2. Photonic Band Gap restricts photons to move downward.
Hot ColdNarrow Band
Photons Laser GainMedium
Phonons
Light Spectral Distribution vs Position
Three types of insulators are possible: electrical, thermal, & light. We are using the light insulating properties of Photonic Crystals to force the desired narrow-band photons into the Lasing gain medium & rethermalizing the remaining out-of-band photons into the desired band for further extraction.
Project Summary
29
Energy Separation - IIEnergy Separation - II
Cold
Hot
PhotonicCrystal
LasingMedium
Designing thespectral and directionalProperties of PCS is a
hard synthesis problem.
Project Summary
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Contents
Introduction to Applications of Photonic Band Gap (PBG) Material
What is a Photonic Band Gap Material?
Generating Electricity from Spectral & Directional Control of IR Radiation
Controlling Thermal Radiation for IR Camouflage
Pumping Laser Weapons with PBG & Thermal Radiation
Initial Experimental Studies On PBG Thermal radiation control
Project Summary
31
Photonic Crystals:Thermal Radiation Control in IR
Three-dimensional photonic crystal emitter for thermophotovoltaic power generation, Lin et al.,(2003) Sandia Labs
Photonic-crystal enhanced narrow-band infrared emitters, Pralle et al. (2002) Ion Optics
Enhancement and suppression of thermal emission by a three-dimensional photonic crystal, Lin et al. (2000) Sandia Labs
Direct calculation of thermal emission for three-dimensionally periodic photonic crystal slabs, Chan et al.(2006) MIT
Thermal emission and absorption of radiation in finite inverted-opal photonic crystals, Florescu et al.,(2005) JPL&LSU
New, $4.6M, world-class, JEOL JBX-9300FS e-beam lithography system (third of its kind) MDL JPL
512 node, dual-processor IA32 Linux cluster with 3.06 GHz Intel Pentium IV
Xeon processors and 2 GB RAM Super- Mike LSU
Spectral and angular optical FTIR
characterization facilities
Ion Optics Inc.
Project Summary
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BB, Pin = 315 mW, T2 = 420.1 oC
BB, Pin = 130 mW, T1 = 273.4 oC
PC, Pin = 130 mW, T2 = 420.1 oC
– Funneling of thermal radiation of larger wavelength (orange area) to thermal radiation of shorter wavelength (grey area).
BB (273.4oC) and PC (273.4oC) plots have the same input power while the photonic crystal produces lower wavelength photons
BB (420.1oC) and PC (273.4oC) plots have the same peak power wavelength
Funneling of the Thermal RadiationExperimental Results
JPL (micro-fab), Ion Optics (testing), LSU (analysis)
Project Summary
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Conclusions
TPV cell efficiencies can be dramatically improved by employing the spectral and angular control provided by photonic crystals
Dual-band spectral radiation management systems using doubly-periodic photonic crystals are now being designed using a restricted set of “practical” structures
Experimental results confirm the photonic crystal ability to control the thermal radiation properties
New vistas exist for using photonic crystals in lasers, IR thermal signature suppression, and high-power ( non-chemical ) lasers for communications and weapons.