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- Front Matter: Volume 6989
- 3D Photonic Crystals and Volume 2D Photonic Crystals
- Quasi Photonic Crystals
- Probing Photonic Crystals
- Light Emission I
- Light Emission II
- Light Emission III
- Metallic Photonic Crystals
- NLO/Switching I
- Fabrication/Devices I
- NLO/Switching II
- Fabrication/Devices II
- Fabrication/Devices III
- Poster Session
Front Matter: Volume 6989
Front Matter: Volume 6989
Show abstract
This PDF file contains the front matter associated with SPIE Proceedings Volume 6989, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.
3D Photonic Crystals and Volume 2D Photonic Crystals
Light transmission and scattering in engineered colloidal hetero-crystals
Show abstract
Heterogeneous 3-dimensional photonic crystals have been prepared by sandwiching self-assembled opal films and
forced-assembled Langmuir-Blodgett colloidal crystal films. Strong transformation of the transmission spectra of the
light traversing such hetero-crystals has been observed and interpreted in terms of the mismatch between eigenmodes of
these photonic crystals and subsequent strong scattering at the interface between these crystals. Direct measurements of
the spectra of forward scattered light have confirmed the peculiar character of the light scattering at the photonic crystal
interface.
Novel method for fabrication of volume 2D photonic crystals
Show abstract
Photonic crystals are wavelength-scale periodic structures built from dielectrics with different refractive indexes As
standard 2D photonic crystals are fabricated by lithographic methods, but in this case only planar structure can be
obtained. We have adapted stack and draw technique that is usually used for photonic crystal fiber fabrication to develop
volume 2D photonic crystals.
Technology allows fabrication of high contrast structures with air holes as well as low contrast solid-all structures where
air holes are replaced with glass micro rods of refractive index. Use of soft glasses with a high difference in refractive
index allows development of a structure where partial photonic band gap exists. The proposed method offers possibility
of fabrication volume 2D photonic crystal with a diameter in the order of 1 mm and height of a few mm. Large area
photonic crystals are very attractive as new optical material named 'photonic glass' with built-in photonic bandgap
functionality. Preliminary fabrication test were performed for two pairs of soft glasses NC21/F2 and SK222/Zr3. The
considered glasses are thermally matched and are synthesized in-house except of F2 glass (standard Schott glass).
Obtained structures are regular with some defects on the borders between intermediate performs. Some glass diffusion is
observed between Zr3 and SK222 glasses. With this technique a 2D photonic crystal with a hexagonal lattice was
fabricated with a pair of soft glasses SK222 and Zr3. Microrod diameter is 749nm and lattice constant 1110 nm.
Photonic crystal consists of 166421 elements (425 elements on diagonal) and its total surface is about field ~0,178mm2.
Study of local dispersion in photonic crystal waveguide interfaces and hetero-structures
Show abstract
We have recently introduced a novel method to calculate local dispersion relation based on the Finite-Difference Time-domain
and filter diagonalization method, which is suitable for local study of dispersion in optical waveguide, especially
for the cases of non-periodic, curvilinear, and finite waveguides. In this paper, this approach is applied to study the
photonic crystal waveguides at interfaces and double hetero-structure waveguides. We also studied the stretching effect,
which is increasing the lateral distance between neighboring rods along guiding direction on band gap. Hybrid modes at
interface are results of superposition of existing modes in adjacent waveguides. The results present a clear picture of
localization mechanism of cavity modes and the transmission in the double-hetero-structures.
Two-dimensional and 3D multi-component photonic crystals: theory and experiment
Show abstract
We report on an analytical study of the photonic band structure of 2D and 3D multi-component photonic crystals. It is found that both types of crystal demonstrate a quasiperiodic resonant behavior of (hkl) photonic stop-bands as a function of the reciprocal lattice vector, providing a selective ON/OFF switching of nonresonant (hkl) stop-bands. Our predictions are compared with the results of conventional numerical studies using the photonic Korringa-Kohn-Rostocker method. Experimental transmission spectra of a-SiO2 synthetic opals show the OFF-switching of the {111} stop-bands at the filler permittivity of ~1.82, the {200} bands at ~1.63, the {220} bands at ~1.93, and the {311} bands at ~1.75. The (222) photonic stop-band, which is due to the second order diffraction from the (111) planes, cannot be switched OFF in a wide range of filler permittivity values, thus indicating a resonant behavior. The experimental data demonstrate an excellent agreement with the theoretical predictions.
Quasi Photonic Crystals
Gap solitons in nonlinear spatiotemporal photonic crystals and gratings
Show abstract
We have generalized the concept of nonlinear periodic structures to dielectric systems that show
arbitrary spatial and temporal variations of the refractive index. Nonlinear pulse propagation
through these spatiotemporal photonic crystals can be described, for shallow nonstationary
gratings, by coupled mode equations which are a generalization of the traditional equations
used for stationary Bragg gratings. Novel gap soliton solutions are found analytically. They
represent a generalization of the gap solitons in static photonic crystals and resonance solitons
found in dynamic gratings.
Periodically oscillating Anderson localization in random photonic superlattices with resonant units
Show abstract
In strongly disordered systems, where Anderson localization is present, the mean transmittance (<T>) decays
exponentially on average with increasing sample size. However, <T> often shows large fluctuations originating from
extremely rare occurrences of necklaces of resonantly coupled states, possessing almost unity transmission. We show in
this study that in one-dimensional (1D) random photonic systems with resonant layers these fluctuations appear to be
very regular and have a period defined by the localization length ξ of the system. We demonstrate that necklace states are
the origin of these well-defined oscillations. We predict that in such a random system efficient transmission channels
form regularly each time the increasing sample length fits so-called optimal-order necklaces and demonstrate the
phenomenon through numerical experiments. Our results provide new insight into the physics of Anderson localization
in random systems with resonant units.
Light transport in planar dielectric optical waveguides based on the aperiodic Thue-Morse sequence
Show abstract
We present the design of a novel, CMOS compatible, waveguide structure capable of multifrequency transmission bands
with strongly enhanced band-edge states. The concept of the structure is based on the aperiodic Thue-Morse fractal
ordering of dielectric scattering subunits combined with a traditional channel-waveguide scheme. The design of the
waveguide has been carefully optimized in order to ensure its manufacturability within standard CMOS processing. Due
to the lack of translational symmetry, the proposed Thue-Morse waveguide is characterized by multiple photonic
pseudoband-gaps and quasi-localized field states exhibiting large field enhancement effects.
Band gap characterization and slow light effects in periodic and quasiperiodic one dimensional photonic crystal
Show abstract
Slow light offers many opportunities for photonic devices by increasing the effective interaction length of
imposed refractive index changes. The slow wave effect in photonic crystals is based on their unique dispersive
properties and thus entirely dielectric in nature. In this work we demonstrate an interesting opportunity to decrease
drastically the group velocity of light in one-dimensional photonic crystals constructed form materials with large
dielectric constant without dispersion). We use numerical analysis to study the photonic properties of periodic (Bragg
mirror) and quasiperiodic one dimensional photonic crystals realized to engineer slow light effects. Various geometries
of the photonic pattern have been characterized and their photonic band-gap structure analyzed. Indeed, one
dimensional quasi periodic photonic multilayer structure based on Fibonacci, Thue-Morse, and Cantor sequences were
studied. Quasiperiodic structures have a rich and highly fragmented reflectivity spectrum with many sharp resonant
peaks that could be exploited in a microcavity system. A comparison of group velocity through periodic and quasiperiodic
photonic crystals was discussed in the context of slow light propagation. The velocity control of pulses in
materials is one of the promising applications of photonic crystals. The material systems used for the numerical analysis
are TiO2/SiO2 and Te/SiO2 which have a refractive index contrast of approximately 1.59 and 3.17 respectively. The
proposed structures were modelled using the Transfer Matrix Method.
Probing Photonic Crystals
Asymmetry reversal and waveguide modes in photonic crystal slabs
E. F. C. Driessen,
P. O. M. Heemskerk,
D. Stolwijk,
et al.
Show abstract
The measured reflection spectra of two-dimensional photonic crystal slabs consist of an asymmetric peak on
top of an oscillating background. For p-polarized light, the asymmetry of the peak flips for angles of incidence
beyond Brewster's angle. We explain the observed line shapes with a Fano model that includes loss and use a
waveguide model to predict the resonance frequencies of the photonic crystal slab. Finite-difference time domain
calculations support the model and show that the resonance due to a higher order mode disappears when the
substrate refractive index is increased beyond ns = 2.04. This is readily explained by the cut-off condition of
the modes given by the waveguide model.
Optimization of a negative index photonic crystal slab at optical wavelength
Show abstract
There has been an increasing interest in using photonic crystals as negative refraction index slabs for integrated
nanophotonics. According to the superlensing criteria, a refractive index equal to -1 is needed to operate at an arbitrary
wavelength [1-2]. The field distribution is the result of multiple propagation phenomena such as reflection, diffraction,
self collimation and negative refraction. We report on the optimization of focusing properties of a triangular air hole
lattice etched in a III-V semiconductor matrix and present the demonstration of negative refraction by FDTD 3D
calculations. Under isotropy and finite length conditions, light transmission in the second band was investigated for an
incident wave tilted by 0°, 2°, 7° and 15° (E Field parallel to the air holes). The advantage of our method lies in the
existence of Fabry-Pérot effect resulting of interferences between the front and the rear interface of the slab. From the
comparison of each transmission spectrum, the filling factor was adjusted to obtain simultaneously n = -1 and a
maximum of signal to operate at a wavelength of 1.55 micrometers. At least, the validity of this method to produce an
intensity maximum behind the slab was checked by mapping the field with FDTD 3D simulations.
Arrays of selectively grown GaN micro-pyramids: photonic and optical-frequency phonon properties
D. Coquillat,
M. Le Vassor d'Yerville,
P. Arcade,
et al.
Show abstract
An array of GaN micro-pyramids containing a near-surface InxGa1-xN/GaN single quantum well has been fabricated
using selective area epitaxial overgrowth above a patterned silica mask. The pyramid array has been studied by means of
angle-resolved reflection measurements in the near- and mid- infrared optical ranges. We have found that the periodic
array of flat-topped pyramids shows marked resonances in the near-infrared optical range due to resonant Bloch modes
within the extraction cone and that the angular dispersion of these modes exhibits strong photonic crystal characteristics.
The experimental results are in good agreement with the photonic band structure calculated using a scattering matrix
formalism. The mid-infrared optical anisotropy properties of the micro-pyramids were investigated to probe the infrared
active phonons of the pyramid array. The A1(LO) phonon of the InxGa1-xN/GaN single quantum well was identified and
the InN mole fraction was estimated from the mode behaviour.
Approaching quantitative optical diffraction analysis of crystal lattices in opal films
Show abstract
Crystal ordering of opal-based self-assembled photonic crystals fabricated by vertical drawing deposition technique has
been examined by the angle-resolved transmission spectroscopy. Assuming that minima in transmission spectra register
the diffraction resonances occurring at different planes of the crystal lattice, the angle dispersions of these resonances
reflect the ordering of the crystal lattice. Since such dispersions obtained as a function of the angle of light incidence
cannot provide quantitative estimate of the crystal ordering without comparison to the adopted standard, we suggested to
analyse the diffraction resonances as a function of the lattice rotation. This method allows to quantify the lattice ordering
by the accuracy of the repetition of similar diffraction features upon the azimuth angle.
Light Emission I
Analysis of the emission characteristics of photonic crystal LEDs
Show abstract
Photonic crystals are known to enhance the extraction efficiency of LEDs and simultaneously shaping the emission
pattern. In order to determine the radiation pattern we developed a model based on coupled mode theory that takes into
account the lattice pattern, etch depth and the mode distribution. From a basic geometrical consideration a fundamental
limit for the directionality is predicted. The calculations fit well to experimental data obtained from green InGaN LEDs
incorporating a hexagonal PhC revealing a maximum directionality of 31% within 30°. Additional FDTD simulations
were performed for determining quantitatively the extraction efficiency of PhC LEDs compared to LEDs with a
roughened surface. Despite its lower overall extraction efficiency, the PhC LED outperforms a standard LED with
surface roughening within an acceptance angle of 34° due to the higher directionality of the extracted light.
Control of mode volume and radiation dynamics of a slow-light-mode in a quasi-3D photonic crystal configuration
Show abstract
We propose a new approach to realise surface addressable active photonic crystal devices. High Q-factor and low optical
volume can be achieved combining lateral control of the mode size by a local modulation of the planar photonic crystal
parameters, and vertical confinement assisted by a Bragg reflector. The low Q-factor of a 1D PC band edge mode can be
increased up to 40000, while the optical mode volume is limited at the wavelength scale. Experimental results on laser
operation achieved using this strategy in the case of an InP-based PC membrane bonded onto a Si/SiO2 Bragg reflector
will be presented.
Tuning of spontaneous emission in photonic crystals by resonant energy transfer and magnetic fields
Show abstract
The fluorescence of emitters embedded in a photonic crystal is known to be inhibited by the presence of a photonic
pseudo-gap acting in their emission range. Here we present a comparative study of the influence of the pseudo-gap on
the fluorescence emission of either organic dyes or nanocrystals embedded within a photonic crystal. Our results clearly
show that the optical properties of the emitters are primarily controlled by the presence of a pseudo-gap which causes
inhibition of the emission in both cases, regardless of the differences in chemical composition. These findings are mainly
attributed to a decrease of the number of available photonic modes for radiative decay of the emitter in a photonic crystal
compared to the effective homogeneous medium. Furthermore, we show that a photonic crystal can be used to control
the fluorescence energy transfer (FRET) between donor-acceptor (D-A) pairs of dyes. Finally, we show that the
application of an external magnetic field can finely tune the emission characteristics of emitters with a permanent
magnetic moment.
1.5 μm photoluminescence of Er3+ in opal based photonic crystals
Show abstract
The study of the emission properties of opal-erbium oxide nanocomposites in the wide range of erbium
concentrations was carried out. Erbium oxide concentration was varied from 0.25 to 16%wt. Maximal output of the
photoluminescence (PL) took place at 1%wt of erbium oxide concentration. It was shown that the annealing
temperatures from 600 to 900°C were too low to exhibit sufficient emission properties of the erbium-opal composites.
The presence of the erbium silicates Er2SiO5 and Er2Si2O7 in the
opal-erbium nanocomposites was revealed by X-ray
phase analysis. Amorphous silica in opal matrix was not crystallized at the annealing during a few hours at
1000 - 1200°C. The case of the tens hours of annealing the crystoballite phase occurred. No angle dependence of the PL
intensity was observed as a result of degradation of the photonic band gap (PBG) at the annealing of the opal-erbium
oxide nanocomposites. Further modification of the material processing to achieve a strong photonic band gap reflection
peak near 1550 nm with high PL intensity in the
opal-Er2O3 composite is running.
Photonic crystal laser based on activated glass
Show abstract
We present the results of calculations of the generation condition of laser with 1D and 2D PC structures. The spectral
and spatial characteristics of finite length 1D and 2D PC with air-glass-doped layers was examined. For these
calculations we used the transfer matrix formalism. The lazing optimum condition is determined.
Light Emission II
Non-linear effects in luminescence of ZnO inverted opals
W. Khunsin,
P. Lovera,
G. Redmond,
et al.
Show abstract
Photoluminescence spectra of the ZnO carcass of inverted opal have been examined in the conditions of the strong
lightto-structure interaction achieved by matching the photonic bandgaps of these photonic crystals to different parts of the
ZnO emission spectrum. Developing the bands of enhanced spontaneous emission associated with both the emission of
ZnO defects and the emission due to interband electron transitions has been observed. Interpretation has been given
taking into account the coupling of emission to eigenmodes of
3-dimensional photonic crystal and the nature of the
electron states involved in the radiative relaxation.
Control of pattern formation in a single feedback system by photonic bandgap structures
Show abstract
We present the observation of the manipulation of modulational instability in a nonlinear dissipative system by a
periodic photonic lattice. We use a setup based on a photorefractive BaTiO3 crystal in a single feedback mirror
configuration leading to the formation of hexagonal patterns. Additionally, we impose an optical lattice to induce one or
two-dimensional photonic band-gap structures with variable parameters. We show that by varying the lattice periodicity,
thus adjusting the transverse spatial frequencies associated to the bandgap, we can induce patterns of particular
symmetry or suppress the modulational instability when the position of the lattice bandgap coincides with the instability
gain.
Thermal emission properties of 2D and 3D silicon photonic crystals
Show abstract
We present measurements of the thermal emission properties of 2D and 3D silicon photonic crystals using either
localized integrated emission sources or resistively heating the entire photonic crystals with and without substrate.
The in-plane as well as out-of-plane emission properties were recorded and compared to numerical simulation.
Impact of dry-etching induced damage in InP-based photonic crystals
Show abstract
In this work variations of the carrier lifetime in a GaInAsP/InP quantum well in two-dimensional PhC structures etched
by Ar/Cl2 chemically assisted ion beam etching as a function of the processing parameters is investigated. It is shown
that the deposition conditions of the SiO2 mask material and its coverage as well as other process steps such as annealing
affect the carrier lifetimes. However the impact of patterning the semiconductor on the carrier lifetime is dominant,
showing over an order of magnitude reduction. For given PhC lattice parameters, the sidewall damage is shown to be
directly related to the measured carrier lifetimes. A simple qualitative model based on sputtering theory and assuming a
conical hole-shape development during etching is used to explain the experimental results.
Photonic crystal slab mirrors for an ultimate vertical and lateral confinement of light in vertical Fabry Perot cavities
Show abstract
Vertical Fabry Perot cavities (VFPCs) have enabled the realization of devices of great interest, like filters,
photodetectors, VCSELs. In traditional VFPCs, the optical feedback is provided by two distributed Bragg Mirrors
(DBRs). However, DBRs present two major drawbacks: they are generally rather thick mirrors, and they do not allow for
a very high control on the lateral losses of the VFPC. We propose the use of a novel type of mirror, the photonic crystal
slab mirror (PCM) which is able to overcome these limitations. In fact, we demonstrate that PCMs are ultra-thin single-layer
mirrors that exhibit a very high reflectivity, and that allow also for a very tight control of the lateral velocity of
photons, by a convenient engineering of the PCM Bloch modes. This concept will lead to the realization of ultra-compact
and highly resonant VFPCs, interesting for VCSELs, non-linear optics-based devices, imaging, highly sensitive
detectors, or 3D optical communication routing.
Light Emission III
Vertical microcavities based on photonic crystal mirrors for III-V/Si integrated microlasers
Show abstract
The on-coming photonic layer of CMOS integrated circuits needs efficient light sources to treat and transmit the flow of
data. We develop new configurations of III-V/Si vertical cavity lasers coupled to silicon optical waveguides using
mirror/coupler based on photonic crystals. These devices can be fabricated using fully CMOS-compatible technological
steps. Using this approach, the optical gain is provided by the III-V material, while all the remaining part of the optical
cavity is in silicon. The output coupling to the sub-µm waveguides of the CMOS optical layer can then be inherently
optimised since the laser mirror/coupler and the Si output waveguides will be realised together during the same
fabrication step.
It has been demonstrated that photonic crystals membrane can act as very efficient reflectors (PCM-mirrors) for vertical
microresonators. In this communication, the design of a vertical cavity microlaser based on these PCM-mirrors will
be presented. We will show that high Q-factors (>10000) along with strong vertical and lateral confinements can be
achieved. As a first demonstration, experimental results on silicon PhC-mirrors and associated vertical cavities will be
discussed, showing Q factors larger than 2000. Finally, theoretical results on the coupling between such cavities and a
silicon micro-waveguide will be presented.
A comparative study of directive emission from photonic quasicrystals
Show abstract
In this paper, we present a comparative study of the emission properties of line sources embedded in two-dimensional
finite-size aperiodically-ordered "photonic-quasicrystal" slabs made of dielectric cylinders arranged
according to representative categories of aperiodic tilings. Our study, based on a rigorous full-wave numerical
method, indicates the possibility of achieving directive low-sidelobe emission at several frequencies. In this connection,
parametric studies are presented, and similarities and differences with the periodic case are highlighted.
Static and dynamic properties of vertical-cavity surface-emitting semiconductor lasers with incorporated two-dimensional photonic crystals
Show abstract
In oxide-confined Vertical-Cavity Surface-Emitting Lasers (VCSELs) the single-mode radiation is desirable for many
applications. The single longitudinal mode is typical in VCSELs, however transverse optical modes can be controlled
either with a small oxide aperture size [2] or small micropillar-like etched top distributed Bragg reflectors (DBRs) [3].
However, the power radiated from single-mode VCSELs is low and it results in low transmission distance in optical
telecommunication networks. The power can be increased due to the fabrication of wider oxide aperture and wider top
DBR, but than a VCSEL becomes multimode.
Since the last decade photonic crystals had been introduced to control transverse optical modes of VCSELs [4-8]. The
PC is created by periodic modulation of the refractive index in one, two or three space directions. In the VCSELs, the PC
is positioned in top DBR and fabricated due to etching air-filled holes in the DBR. It was demonstrated that the PC
reduces the transverse optical mode number, spectral linewidth [4-8] and increases the modulation bandwidth of
VCSELs [9].
In this paper we present results of the investigated VCSELs with incorporated photonic crystals fabricated using the
focused ion beam (FIB) machine. Power versus current, spectral and modulation characteristics of VCSELs with PC are
investigated and compared to similar VCSELs with etched mesa.
Metallic Photonic Crystals
Plasmonic excitations in ordered assemblies of metallic nanoshells
Show abstract
Periodic nanostructures for plasmonic engineering, comprising one or two types of silica core - metallic shell spherical particles, are studied by means of full electrodynamic calculations using the layer-multiple-scattering method. The complex photonic band structure of such three-dimensional crystals is analyzed in conjunction with relevant transmission spectra of corresponding finite slabs and the physical origin of the different optical modes is elucidated, providing a consistent interpretation of the underlying physics. In the case of binary structures, collective plasmonic modes originating from the two building components coexist, leading to broadband absorption and a rich structure of resonances and hybridization gaps over an extended frequency range.
Tunable Fabry-Perot THz filter with sub-wavelength grating mirrors
Thorsten Goebel,
Daniel Schoenherr,
Cezary Sydlo,
et al.
Show abstract
We utilize the reflectivity of one-dimensional metal gratings with sub-wavelength slits to realize mirrors for THz
frequencies. Two of them are combined to a Fabry-Perot filter, which features the corresponding transmission
bands. By appropriate choice of dimensions, the extraordinary transmission resonance of the sub-wavelength
gratings can be superimposed with the Fabry-Perot peak. By varying the resonator length between the grating
mirrors, the overlap of both transmission peaks can be controlled. This enables the tuning of the filter bandwidth.
The theoretical analysis shows that continuous tuning of the filter bandwidth up to 30% is possible for a two
mirror stage. For the performance of comparative measurements, an all-fiber continuous-wave THz system is
used. The experimental results are in fairly well agreement with the theoretically predicted tuning properties.
Coupled surface states in one- and two-dimensional frequency dependent photonic crystals
Show abstract
One-dimensional photonic crystals with a frequency dependent material such as a metal or a
polaritonic substance have very interesting properties. Their band structure can be calculated by
a Kronig-Penney like equation where one uses next to the Bloch condition the continuity of the
field and its derivative. The bulk absorption behaviour can be observed in the band structure as
well but the size of the band gap is decreased proportional to the thickness of the frequency
dependent layers. These absorption band gaps are complete for both polarisations and all angles of
incidence except for modes propagating parallel to the surface. In this work these surface
solutions are compared with ordinary surface plasmons and polaritons propagating on a simple
metal/polaritonic to air interface. The band structure calculation of a two-dimensional frequency
dependent photonic crystal is much more complicated. For a metallic photonic crystal flat bands
occur in the band structure for a certain polarisation which are the surface plasmon (Mie)
resonances. We show resulting the field enhancement by calculating the local density of
states. Furthermore we investigate the band gap for the second polarisation and design a W1
wave-guide to demonstrate the localisation of the electromagnetic field.
Dynamic optical gratings in two layer system: ferroelectric and nanostructured metal film
Show abstract
Dynamic reflection gratings, recorded by the single laser beam in ferroelectric crystals covered by nano-structured
golden film generate optical and electrical pulsations. Frequency and amplitude of pulsations depend on laser intensity,
the ambient pressure and temperature.
Model explaining pulsations are developed based on the photogalvanic and pyroelectric mechanisms of holographic
grating recording. Possible applications for the remote pressure and temperature sensing are discussed.
Golden nanostructured film increase significantly sensitivity of the crystal pulsations to laser intensity, temperature and
pressure. For a focused HeNe laser beam (intensity about 160mW/cm2) an interesting phenomenon (deserving special
considerations) of self-phase conjugation was observed.
NLO/Switching I
Second harmonic localization in nonlinear photonic crystals
Show abstract
We demonstrate an isotropic phase matching condition achieved in nonlinear 2D PhCs that suppresses the incident angle
constraint [1]. In addition, we show a backward SH localization effect by combining this unusual all-angle phase
matching and left-handed PhC properties. The SH emission is confined in a small area of dimension close to the pump
wavelength without the introduction of defect lattices. An analytical model is proposed in order to explain this parametric localization mechanism.
Nonlinear photonic structures for all-optical deflection
Show abstract
We demonstrate both experimentally and numerically continuous all-optical deflection achieved in specially designed
photonic structures in quadratic nonlinear materials and discuss their special properties using Fourier space analysis. We
designed and manufactured the proposed structures in a Stoichiometric Lithium Tantalate crystal. The inverted domains
consist of a set of arcs arranged in the propagation direction. This arrangement results in a periodic pattern in the
propagation direction and a chirped pattern in the transverse direction. A second harmonic generation experiment was
performed on the crystal structures to examine the phase matching properties. Varying the pump wavelength from 1545
nm to 1536 nm at 150°C resulted in continuous angular deflection of the second harmonic wave up to ~2.5°. Continuous
deflection was also obtained by varying the crystal temperature at a fixed pump wavelength. These structures can be
used for various all-optical deflection applications, e.g. all-optical router using two cascaded nonlinear processes: an up-conversion
process of signal and control beams, where the output channel is controlled by the frequency of the
controlling beam, followed by a down conversion process, creating a beam at the signal frequency in the desired channel.
Quick and non-invasive method for characterisation of profiles of nano-photonics structures
Show abstract
Depth and profile information of one or two-dimensional photonic crystals can be obtained through
measurements of reflective diffractive patters obtained from the structures and subsequent numerical analysis. The
technique is known as a scatterometry. The method is non-invasive and fast, and competitive to the alternatives of AFM,
SEM etc. In our paper we presented results of investigation 1D photonic crystal fabricated in GaN with period
Λ = 400 nm, fill factor ff = 50% and depth d = 400 nm. Using computer algorithm of Rigorous Coupled Wave Analysis
(RCWA) and measuring diffracted light we extracted the profile parameters of Λ = 420 nm, ff = 51%, d = 400 nm.
Possibility of application of our method for analysis 2D photonic crystals is discussed also.
Few-cycle pulses interactions in nonlinear photonic crystals with managed dispersion
Show abstract
Novel effects for few-cycle pulses propagation in quadratic media with dispersion management are considered. First, the
process of extraordinary wave generation in uniaxial crystal is tightly related with the process of ordinary wave profile
differentiation. Velocity mismatch limits interaction efficiency and leads to splitting of generated waves into two subpulses.
Such effect can be suppressed in the medium with periodic modulation of quadratic nonlinearity or with velocity
mismatch sign modulation. Second, highly interesting effects arise with the third-order dispersion. Dispersive spreading
can be reduced in layered medium with alternating third-order dispersion coefficients. Quadratic photonic crystals with
modulated dispersion coefficients or with managed dispersion are very promising for few-cycle pulse nonlinear optics.
One- and two-wave soliton trapping and propagation dynamics are also studied in such crystals. The analytical theory is
accompanied with the numerical simulation results.
Fabrication/Devices I
High-transmission 1D photonic crystal/photonic wire multiple cavity structures based on silicon-on-insulator
Show abstract
This paper describes the design, modeling, fabrication and characterization of single-row photonic crystal multiple micro-cavity structures embedded in 500 nm photonic wire waveguides. The strength of coupling between the resonators and the free spectral range (FSR) between the split resonance frequencies of the coupled-cavity combination were controlled via the use of different numbers of periodic hole structures - and through the use of different aperiodic hole taper arrangements between the two cavities in the middle mirror section of the mirrors. Both 2D and 3D finite-difference time-domain (FDTD) computations have been used to simulate the device structures. Comparisons have been made with the results of measurements and show good agreement.
Quality factor optimization of photonic crystal cavities through multiple multipole expansion technique and power loss integral
Show abstract
The Local Density of photonic States (LDOS) and Multiple Multipole Expansion technique (MME) are powerful tools in the study of spontaneous emission and calculation of photon confinement as well as efficient calculation of stationary field in planar photonic crystals. We bridge between optimization of Purcell factor and Q-factor in photonic crystal micro-cavities on one hand, and cavity power loss on the other hand. The quality factor calculated through a pulse response technique based on Finite Difference Time Domain (FDTD) simulations are compared with quality factor calculated by other approaches of LDOS and power loss. It turned out that the latter methods are more accurate and computationally less expensive. The cavity power loss is defined as the surface integration of energy density flow projected toward outside of the effective cavity volume. It is shown that size changes and shifting the neighboring rods or holes have a large impact on the mode volume and confinement. The quality factor optimization is performed for a H1- photonic crystal cavity, and mode volume investigations carried out for high Q factor arrangements. These investigations are resulted in effective structural design rules and geometrical freedom contour plots for the neighboring rods in the vicinity of the micro-cavity. These generalized design rules are suitable for further studies in other photonic micro-cavities.
NLO/Switching II
Novel design of photonic crystal dense wavelength multiplexer based on nonlinear effect
Show abstract
Using a two-dimensional Finite-difference time-domain method (2D FDTD), we present an extensive study of a new
type of the wavelength multiplexer system. The self focusing and defocusing of the light beam are considered in this
paper. The coupling between different kinds of components integrated in the same chip, in terms of coupling efficiency,
is evaluated. Ultra-Dense Wavelength Division Multiplexing system (UDWDM) is of increasing demand since it
provides large broad spectra that satisfy large number of users
world-wide. This system can be used in the high-capacity
optical fibre communication systems. The UDWDM plays a central role in optical interconnection required for high-dense integrated systems, in terms of light coupling between various optical chips.
All-optical diode action with Thue-Morse quasiperiodic photonic crystals
Show abstract
We theoretically investigate the possibility of realizing a nonlinear all-optical diode by using the
unique field-localization properties (known as Anderson-Kohmoto localization) of Thue-Morse
quasiperiodic 1D photonic crystals. The interplay between the intrinsic spatial asymmetry in
odd-order Thue-Morse lattices and Kerr nonlinearity gives rise to sharp resonances of perfect
transmission that can be used to give a polarization-insensitive, nonreciprocal propagation with
a contrast close to unity for low optical intensities. Such nonlinear diode would also represent
the first all-optical device which is crucially based on Anderson-like localization.
Switching of electromagnetic eigenwaves in metastructures
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Switching effect based on controlled field redistribution inside the structure is analyzed for
glass, silicon and Si/SiO2 linear photonic crystals covered with Kerr nonlinear film. The spectrum and
amplitude distribution for several types of 1D states: band, surface and pure local states are for Si/SiO2
photonic structures are studied. The nonlinear shift of bandgap position in Si/SiO2 linear photonic
crystals covered with Kerr nonlinear film is investigated. Two schemes of all-optical signal processing
are considered.
Fabrication/Devices II
Efficient coupling of light between single-mode waveguides and supercollimating photonic crystals
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We study the coupling of light between strip and rib waveguides and supercollimating photonic crystals on
silicon-on-insulator substrates. The dispersive properties of the supercollimating photonic crystal are used to
define the design requirements on the excitation waveguide and the boundary of the photonic crystal is optimized
to improve the impedance matching between the two structures. By 3D calculations, we find that rib waveguides
can yield transmission effciencies up to about 96 % and reflections lower than 0.2 % at wavelengths close to
1.55 μm, while insuring single-mode propagation. This work therefore constitutes an important step toward the
integration of supercollimation-based optical circuits on photonic chips.
Novel multiplexer/demultiplexer based on photonic crystal superprism
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We report a novel type of dispersive structure for wavelength multiplexer/demultiplxer based on a 2D photonic
crystal (PC) prism. The novel device is proposed using super dispersion of a 2D PC. Simulation is carried out to
determine the angular dispersion as a function of the period. The design has been optimized to improve the
performance of a system with moderate refractive index contrast. It is shown that by varying the incident angle in a
wavelength range from 1.3μm to 1.5μm, a superprism effect is observed. The performance of the devices is
investigated in terms of sensitivity and resolution, which would help to understand the behaviour of the superprism
prior to fabrication and its integration in photonic circuits.
Fabrication/Devices III
Design criteria and 3D FEM modeling of air hole photonic crystal
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This work presents a detailed numerical Finite Element Method FEM modeling for passive optical components such as
photonic crystals (PhCs). The accurate modeling characterizes the PhCs structures by considering the field resonance
and the radiation behavior of the periodic pattern. The frequency responses at each side of the photonic crystal are
evaluated by considering the 3D periodic structure enclosed in a black box with six input/output ports. This scattering
matrix approach (SMA) is useful in order to evaluate in plane and vertical PhCs the resonance of the photonic crystal.
Through the analysis of all the frequency responses we characterize the passband regions and the stopband regions of
the PhC slab.
Temperature tuning of ultra-high Q/V SOI microcavities
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Ultrahigh Q/V lineic silicon Fabry Perot (FP) microcavities relying on silica substrate have been fabricated. Two cavities
designs are studied based respectively on cavity mode losses recycling and on mirrors with tapered sections. The
experimental evolution of cavities characteristics are studied as a function of sample temperature. The authors achieve a
quality factor of 58000 for a modal volume of 0.6 (λ/n)3.
Rod shape optimization in photonic crystal bends by the finite element method
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Modal solutions for Photonic Crystal with circular and square shaped rods have been obtained using the Finite
Element method. We compare the field distributions and effective indices with rod shape in the Photonic
Crystal. We optimize sharp 90° bends with different rod shape using a Finite Element Time Domain method.
Photonic crystal waveguide arrays
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We carry out the study of two-dimensional photonic-crystal waveguide arrays (PCWA) composed of N waveguides
coupled evanescently with each other. The coupling properties of the waveguide modes are investigated using coupledmode
theory. One straightforward application of such an analysis is to channel input power from a central waveguide to
side waveguides. As a result, the appropriate designs of PCWAs may permit the realization of efficient, compact and
novel power dividers. For instance, we show that power dividers, switchers, and Mach-Zehnder interferometers can be
feasible using N=3 channels. On the other hand, N=5 waveguides can split the input power by 1/4 at a certain length.
Photonic crystal-based WDM filter for integrated optical triplexer transceiver
Show abstract
We propose the new concept of an optical triplexer for an application of Gigabit Ethernet Passive Optical Network (GEPON)
to Fiber-To-The-Home (FTTH) network. Based on a photonic crystal structure with local point defects, the optical
triplexer is optimally designed. The proposed device is analyzed by the plane wave expansion method and its
performance characteristics are evaluated by the finite-difference time-domain method. The optical triplexer proposed
here is designed to have a compact size of about 4 × 3 μm2 and the extinction ratios of -32.33 dB for 1310 nm, -19.84 dB for 1490 nm and -29.93 dB for 1550 nm, respectively.
Poster Session
Complete photonic band gap in icosahedral quasicrystals with a body-centered six-dimensional lattice
Show abstract
For the first time, the band structure of three-dimensional cubic photonic approximants of quasicrystals is studied
theoretically. The approximants of different orders are found to have large, near-isotropic band gaps in a wide range of
permittivity values. The effect of atom coordination on the size and threshold of the photonic band gap is explored. The
existence of a complete band gap in the cubic photonic quasicrystal with a body-centered six-dimensional lattice is
demonstrated.
Holographic fabrication of hierarchical nanostructures using microprism array toward optofluidic integration
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Holographic lithography provides a highly compatible and facile way to fabricate multi-dimensional periodic
nanostructures. Periodic nanostructures have useful applications not only as biological substrates or catalytic supports
but also as nanophotonic devices with various photonic properties such as photonic band-gap (PBG), localized surface
plasmon resonance (LSPR) or surface enhanced Raman scattering (SERS). In combination with single refracting prism
holographic lithography and conventional photolithography, we could achieve the micrometer-scale patterns of periodic
nanostructures which can be integrated in microfluidic chip. With the help of conventional MEMS technologies, Arrays
of pyramid shape and top-cut pyramid shape microprism can be prepared. Single laser exposure step through the
microprism arrays (MPAs) can be generate multiscale patterns of 2D and 3D nanostructures. As prepared nanostructures
combined with microfluidic chip is a highly efficient optofluidic platform which is applicable to the chemical and biosensors.
Dispersion and symmetry properties of anisotropic photonic crystals of arbitrary geometry and dimension
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This work presents a fully vector plane wave method suitable for eigenwaves characteristics calculation for periodic
dielectric media with arbitrary geometry and dimension, consisting of either isotropic or anisotropic materials. Using the
method concerned, the influence of anisotropic material molecules reorientation in a photonic crystal on the symmetry
properties of the dispersion surface of the latter. The work explains how the 2D anisotropic photonic crystal Brillouin
zone shape depend on the anisotropic molecules orientation.
Periodic NLC phase grating for tuneable PBG applications
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The advent of nanolithographic techniques has enabled electrically-driven liquid crystal devices to be addressed
using nanoscale electrodes. Tiny periodic phase grating structures, which can now be realized, may find applications
in optical communications and displays devices. Introducing optical discontinuities in the nematic liquid
crystal (NLC) material will enable these structures to act as photonic band gap devices. This paper addresses the
properties of band gap structures formed by NLC discontinuities using a 10micron thick homeotropically aligned
NLC. It demonstrates how the position of the optical discontinuities may be altered by a symmetric voltage pattern
and thus tune the photonic band gap.