Post on 06-Oct-2020
ωħ
eµB
COLLOIDAL PHOTONIC CRYSTALS AND
SUPERLATTICES FOR PHOTONIC APPLICATIONS
WP6 NANOPHOTONICS, Koen Clays
Overview:• Introduction to Photonic Crystals and colloidal PC’s• Photonic heterostructures: BANDGAP ENGINEERING• Fluorescence inhibition (steady-state) and
non-exponential decay (time-resolved)Spectral narrowing of fluorescence(for LASING)Improved Fluorescence Resonance Energy-
Transfer (FRET) in photonic crystals (for LIGHT HARVESTING)
• Magnetic effects in quantum dots vs. closed shell• New avenues: inverted opals, hollow spheres, titania spheres,
vortex pinning, ...
colloidal photonic crystals by convective self-assembly
Well-ordered arrays of colloidsRefractive index changes periodicallyPhotonic band structure arises
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1500 1600 1700 1800 1900 2000 2100 2200 2300
optic
al e
xtin
ctio
n
wavelength (nm)J. Chem. Phys. 118(23), 10752 (2003)
SANS data over an area of 0.7 cm2 from a photonic crystal composed of 270 nm silica spheres depositedby convective self-assembly.
photograph of optical diffraction pattern for different laser wavelengths and schematic theoretical pattern:
Overview:• Introduction to Photonic Crystals and colloidal PC’s
• Photonic heterostructures: BANDGAP ENGINEERING
• Fluorescence inhibition (steady-state) and non-exponential decay (time-resolved)
Spectral narrowing of fluorescence(for LASING)Improved Fluorescence Resonance Energy-
Transfer (FRET) in photonic crystals (for LIGHT HARVESTING)
• Magnetic effects in quantum dots vs. closed shell• New avenues: inverted opals, hollow spheres, titania spheres, vortex
pinning, ...
Introduction of functionality: Langmuir – Blodgett Monolayers
450 500 550 600 650 700 750 800 850
0.0
0.2
0.4
0.6
0.8
1.0
1.2
a after step 3 after step 2 after step 2 307 nm LB film
Opt
ical
Den
sity
(arb
. uni
ts)
Wavelength (nm)
Introduction of functionality: Langmuir – Blodgett Monolayers
Analysis of spectral position of defect mode as function of sphere diameter of top and bottom stack if single layer defect in crystal of 415 nm spheres:
conclusion:” impurity “ doping analogous to P- or N-doping in semiconductors, is possible
Langmuir 19, 4465 (2003); Appl. Phys. Lett. 82(21) 3764 (2003), Chem. Phys. Lett. 422, 251 (2006)
Demonstration of periodic nature of defect mode: spectral position of allowedpassband in forbidden stopband shows importance of phase:
Chemical Physics Letters 422, 251-255 (2006) collaboration with Prof. Serge Ravaine, Centre de Recherche Paul Pascal, Université Bordeaux I, France
Chem. Phys. Lett. 422, 251 (2006)
Overview:• Introduction to Photonic Crystals and colloidal PC’s• Photonic heterostructures: BANDGAP ENGINEERING
• Fluorescence inhibition (steady-state) and non-exponential decay (time-resolved)
Spectral narrowing of fluorescence(for LASING)Improved Fluorescence Resonance Energy-
Transfer (FRET) in photonic crystals (for LIGHT HARVESTING)
• Magnetic effects in quantum dots vs. closed shell• New avenues: inverted opals, hollow spheres, titania spheres, vortex
pinning, ...
Fluorescence Inhibition
Fluorescence Inhibition
Chem. Phys. Lett. 421, 1 (2006)
Non-exponential fluorescence decay in photonic crystals: Experiments
Distribution of the most frequent rate γmf in the reference (full) and PSB (dash), ∆γ is a parameter for the width of the distribution
Locally the crystals are quite heterogeneous, the reference more so than the PSB. In the PSB sample, widths are consistently smaller than in the reference samples
Physical Review B 2007, accepted
Non-exponential fluorescence decay in photonic crystals: Simulations
Spectral narrowing of fluorescence
• We were able to insert a 2D defect into a photonic crystal. This was not sufficient to induce spectral narrowing.
• BANDGAP ENGINEERING: heterostructure: broader stopband, deeper and wider passband
Vs.
Spectral narrowing of fluorescence
ABAB heterostructure: Both suppression and enhancement of emission gives spectral narrowing, a necessary, yet not sufficient, condition for LASING!!
J. Appl. Phys. 100, 123112 (2006)
Overview:• Introduction to Photonic Crystals and colloidal PC’s• Photonic heterostructures: BANDGAP ENGINEERING• Fluorescence inhibition (steady-state) and
non-exponential decay (time-resolved)Spectral narrowing of fluorescence (for LASING)
Improved Fluorescence Resonance Energy-Transfer (FRET) in photonic crystals (for LIGHT HARVESTING)
• Magnetic effects in quantum dots vs. closed shell• New avenues: inverted opals, hollow spheres, titania spheres, vortex
pinning, ...
Förster Resonance Energy Transfer (FRET): intro
Figure . The energy transfer efficiency of a Cy3/Cy5 FRET pair[9].
FRET enhancement in photonic crystals: solution benchmark
The distance between a donor (Cy3) and an acceptor (Cy5) was controlled with an oligonucleotide linker. In solution we observe fluorescence resonant energy transfer (FRET). EET is 38% for the red curve and 45% for the black curve.
FRET enhancement in photonic crystals: from 37 to 61% efficiency for LIGHT HARVESTING !!
Chemistry of Materials, accepted
Overview:• Introduction to Photonic Crystals and colloidal PC’s• Photonic heterostructures: BANDGAP ENGINEERING• Fluorescence inhibition (steady-state) and
non-exponential decay (time-resolved)Spectral narrowing of fluorescence(for LASING)Improved Fluorescence Resonance Energy-
Transfer (FRET) in photonic crystals (for LIGHT HARVESTING)
• Magnetic effects in quantum dots vs. closed shell
• New avenues: inverted opals, hollow spheres, titania spheres, vortex pinning, ...
500 600 700 800
0.2
0.4
0.6
0.8
1.0
1.2
Ext
inct
ion
Wavelength (nm)
PC2
0.0
0.2
0.4
0.6
0.8
1.0
N
orm
aliz
ed F
L In
tens
ity Rhodamine B Quantum dot
Possibility to use magnetic field to additionally control the lightPhotonic crystal made from silica filled with
Closed shell organic chromophore: RhodamineB dyeMagnetic particle: CdSe/ZnS quantum dot
500 550 600 650 700
-0.1
0.0
0.1
0.2
0.3
Red
uced
FL
Inte
nsity
Wavelength (nm)500 550 600 650 700
-0.20
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
Red
uced
FL
Inte
nsity
Wavelength (nm)
RhB CdSe/ZnS
Time resolved fluorescence measurements
RhB
CdSe/ZnS
Overview:• Introduction to Photonic Crystals and colloidal PC’s• Photonic BANDGAP ENGINEERING• Fluorescence inhibition (steady-state) and
non-exponential decay (time-resolved)Spectral narrowing of fluorescence(for LASING)Improved Fluorescence Resonance Energy-
Transfer (FRET) in photonic crystals (for LIGHT HARVESTING)
• Magnetic effects in quantum dots vs. closed shell
• New avenues: inverted opals, hollow spheres, titania spheres, vortex pinning, ...
Inverted opal, in collaboration withChris Summers, GATech:
SEM Analysis:
Large Sphere “defect” layer
Vortex pinning
Nano-engineering magnetic-field inducedsuperconductivity by vortex pinning by periodic arrays of magnetic dots:
Niobium deposited on nanospheres of silicaon mica
Conclusions:
PHOTONIC BANDGAP ENGINEERING in self-assembledcolloidal photonic crystals can provide:
1. spectral narrowing of fluorescence, a necessary (notsufficient) condition for LASING
2. improved energy transfer efficiency for LIGHT HARVESTING
Who
• Kurt Wostyn• Yuxia Zhao• Kai Song, • Wim Libaers, • Kasper Baert, fluorescence, time-resolved• Yanqiu Jiang, titania, hollow spheres• Luis Gonzalez, spincoating photonic crystals• Branko Kolaric, colloid chemistry, FRET, INPAC Postdoc• Renaud Vallée, fluorescence analysis
• Prof. Serge Ravaine, Université Bordeaux I• Prof. Christophe Summers, Georgia Institute of Technology