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Polarization effects in optical spectra of photonic crystals

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Polarization effects in optical spectra of photonic crystals Anton Samusev Saint Petersburg State Polytechnical University, Ioffe Physico-Technical Institute – PowerPoint PPT presentation

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Title: Polarization effects in optical spectra of photonic crystals


1
Polarization effects in optical spectra of
photonic crystals

Anton Samusev
Saint Petersburg State Polytechnical
University, Ioffe Physico-Technical Institute
JASS05 30 March 9 April, 2005
2
Overview
  1. Photonic band gap structure of artificial opals
  2. Optical polarization-resolved study of photonic
    crystals limited experimental data
  3. Polarization effects in transmission spectra of
    artificial opals
  4. Fresnel theory and Brewster effect (semi-infinite
    homogeneous medium)
  5. 3D diffraction of light in opals strong
    polarization dependences
  6. Conclusions

3
Bragg Diffraction
4
Energy gap in electromagnetic spectrum
Increasing of the dielectric contrast could lead
to the overlapping of energy gaps in any
direction in 3D space.
5
Angular-resolved transmission spectra of
artificial opals
Bandgap position for different incident angle
directions
6
Photonic Bandgap Structure of Artificial Opals
7
Experimental evidence of polarization dependence
in reflectivity spectra of artificial
opalsGalisteo-Lopez et al, Appl. Phys. Lett.
82, 4068 (2003)
0 lt ?ext lt 39 450nm lt ? lt 700nm
8
Bragg diagrams
9
Light coupling to single and multiple sets of
crystallographic planes
10
Fresnel formulas
n1 ? n2 gt qt ? qi and aB ? 45
11
LgKL scanning plane

12
Polarization dependences of photonic gaps.
Analogy with Fresnel theory. Brewster angle.
13
Polarization peculiarities in transmission
spectra of opals(theoretical and experimental
results by A.V. Selkin and M.V.Rybin)
Calculation
Experiment
400
00
14
Fabrication of artificial opals
There are 3 in-layer position A red B blue
C green Layers could pack in fcc lattice
ABCABC or ACBACB hcp lattice ABABAB
Silica spheres settle in close packed hexagonal
layers
15
Diffraction Experimental Scheme
  • Laser beam propagates through
  • Depolarizer
  • Polarizer
  • Lens in the center of the screen
  • Reflects from the opal sample

16
During an experiment

17
Diffraction pattern from high quality opal
structure fcc I (ABCABC)
fcc I
-110
18
Diffraction pattern from high quality opal
structure fcc II (ACBACB)
fcc II

-110
19
Diffraction pattern from a twinned opal structure
fcc I fcc II (ABCACBA)
fcc Ifcc II

-110
20
Diffraction pattern on strongly disordered opal
structure

-110
21
Bragg diffraction patterns in-110 geometry
22
Processed images
23
Image analysis process
1. Modification of the screen image shape
2. Profile plotting and searching for a peak in
I(a) dependence intensity as a function of
coordinate along section
24
Q 0o
25
Q 10o
26
Q 20o
27
Q 30o
28
Q 40o
29
Q 50o
30
Q 60o
31
Q 70o
32
Q 80o
33
Q 90o
34
Q 100o
35
Q 110o
36
Q 120o
37
Q 130o
38
Q 140o
39
Q 150o
40
Q 160o
41
Q 170o
42
Q 180o
43
Intensity as a function of polarization angle
I(Q)
44
Conclusions
  1. It is demonstrated that transmission and
    diffraction measurements provide quantitative
    information on the complex interaction of
    polarized light with three-dimensional photonic
    crystals.
  2. The polarization-resolved transmission spectra
    can be discussed in terms of the Fresnel theory
    and the Brewster effect taken into account
    three-dimensional photonic structure of synthetic
    opals.
  3. Our diffraction data shows experimental evidence
    of strong polarization dependence even far from
    Brewster angle.
  4. These experimental results and conclusion bridge
    optical spectroscopy of photonic crystals and
    optical spectroscopy of conventional bulk
    homogeneous materials.

45
The l versus 1 cos (q) dependence
linearization
514,5 nm
496,5 nm
488,0 nm
476,5 nm
457,9 nm
  • Theoretical calculation
  • (V.A.Kosobukin)
  • neffd(1 cosq)
  • neff _at_ 1,365
  • d _at_ 268 nm

46
(No Transcript)
47
Artificial Opal
Artificial opal sample (SEM Image) Several
cleaved planes of fcc structure are shown
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