Showing papers on "Photonic crystal published in 2004"
TL;DR: The fabrication—through direct laser writing—and detailed characterization of high-quality large-scale f.c. c.
Abstract: The past decade has witnessed intensive research efforts related to the design and fabrication of photonic crystals1,2. These periodically structured dielectric materials can represent the optical analogue of semiconductor crystals, and provide a novel platform for the realization of integrated photonics. Despite intensive efforts, inexpensive fabrication techniques for large-scale three-dimensional photonic crystals of high enough quality, with photonic bandgaps at near-infrared frequencies, and built-in functional elements for telecommunication applications, have been elusive. Direct laser writing by multiphoton polymerization3 of a photoresist has emerged as a technique for the rapid, cheap and flexible fabrication of nanostructures for photonics. In 1999, so-called layer-by-layer4 or woodpile photonic crystals were fabricated with a fundamental stop band at 3.9 μm wavelength5. In 2002, a corresponding 1.9 μm was achieved6, but the important face-centred-cubic (f.c.c.) symmetry was abandoned. Importantly, fundamental stop bands or photonic bandgaps at telecommunication wavelengths have not been demonstrated. In this letter, we report the fabrication—through direct laser writing—and detailed characterization of high-quality large-scale f.c.c. layer-by-layer structures, with fundamental stop bands ranging from 1.3 to 1.7 μm.
1,054 citations
TL;DR: In this paper, the spectral distribution and time-dependent decay of light emitted from excitons confined in the quantum dots are controlled by the host photonic crystal, and both inhibited and enhanced decay rates are observed depending on the optical emission frequency.
Abstract: Control of spontaneously emitted light lies at the heart of quantum optics. It is essential for diverse applications ranging from miniature lasers and light-emitting diodes, to single-photon sources for quantum information, and to solar energy harvesting. To explore such new quantum optics applications, a suitably tailored dielectric environment is required in which the vacuum fluctuations that control spontaneous emission can be manipulated. Photonic crystals provide such an environment: they strongly modify the vacuum fluctuations, causing the decay of emitted light to be accelerated or slowed down, to reveal unusual statistics, or to be completely inhibited in the ideal case of a photonic bandgap. Here we study spontaneous emission from semiconductor quantum dots embedded in inverse opal photonic crystals. We show that the spectral distribution and time-dependent decay of light emitted from excitons confined in the quantum dots are controlled by the host photonic crystal. Modified emission is observed over large frequency bandwidths of 10%, orders of magnitude larger than reported for resonant optical microcavities. Both inhibited and enhanced decay rates are observed depending on the optical emission frequency, and they are controlled by the crystals’ lattice parameter. Our experimental results provide a basis for all-solid-state dynamic control
of optical quantum systems.
1,046 citations
Journal Article•
TL;DR: This work shows that the spectral distribution and time-dependent decay of light emitted from excitons confined in the quantum dots are controlled by the host photonic crystal, providing a basis for all-solid-state dynamic control of optical quantum systems.
Abstract: Control of spontaneously emitted light lies at the heart of quantum optics. It is essential for diverse applications ranging from miniature lasers and light-emitting diodes, to single-photon sources for quantum information, and to solar energy harvesting. To explore such new quantum optics applications, a suitably tailored dielectric environment is required in which the vacuum fluctuations that control spontaneous emission can be manipulated. Photonic crystals provide such an environment: they strongly modify the vacuum fluctuations, causing the decay of emitted light to be accelerated or slowed down, to reveal unusual statistics, or to be completely inhibited in the ideal case of a photonic bandgap. Here we study spontaneous emission from semiconductor quantum dots embedded in inverse opal photonic crystals. We show that the spectral distribution and time-dependent decay of light emitted from excitons confined in the quantum dots are controlled by the host photonic crystal. Modified emission is observed over large frequency bandwidths of 10%, orders of magnitude larger than reported for resonant optical microcavities. Both inhibited and enhanced decay rates are observed depending on the optical emission frequency, and they are controlled by the crystals’ lattice parameter. Our experimental results provide a basis for all-solid-state dynamic control
of optical quantum systems.
1,019 citations
TL;DR: In this article, different properties possible to obtain in photonic crystal fibers are reviewed and fabrication and modeling methods are also discussed, and different properties of photonic bandgap effect are discussed.
Abstract: Photonic crystal fibers are a new class of optical fibers. Their artificial crystal-like microstructure results in a number of unusual properties. They can guide light not only through a well-known total internal reflection mechanism but using also photonic bandgap effect. In this paper different properties possible to obtain in photonic crystal fibers are reviewed. Fabrication and modeling methods are also discussed.
995 citations
TL;DR: The experimental demonstration of an electrically driven, single-mode, low threshold current (∼260 μA) photonic band gap laser operating at room temperature is reported, a small step toward a thresholdless laser or a single photon source.
Abstract: We report the experimental demonstration of an electrically driven, single-mode, low threshold current (∼260 μA) photonic band gap laser operating at room temperature. The electrical current pulse is injected through a sub-micrometer-sized semiconductor wire at the center of the mode with minimal degradation of the quality factor. The actual mode of interest operates in a nondegenerate monopole mode, as evidenced through the comparison of the measurement with the computation based on the actual fabricated structural parameters. As a small step toward a thresholdless laser or a single photon source, this wavelength-size photonic crystal laser may be of interest to photonic crystals, cavity quantum electrodynamics, and quantum information communities.
831 citations
TL;DR: If all-optical devices using photonic crystal designs promise to be smaller than the wavelength of light, and to operate with bandwidths that are very difficult to achieve electronically, operation at single-photon power levels could be feasible.
Abstract: The quest for all-optical signal processing is generally deemed to be impractical because optical nonlinearities are usually weak. The emerging field of nonlinear photonic crystals seems destined to change this view dramatically. Theoretical considerations show that all-optical devices using photonic crystal designs promise to be smaller than the wavelength of light, and to operate with bandwidths that are very difficult to achieve electronically. When created in commonly used materials, these devices could operate at powers of only a few milliwatts. Moreover, if these designs are combined with materials and systems that support electromagnetically induced transparency, operation at single-photon power levels could be feasible.
776 citations
TL;DR: In this paper, the most important properties of lithium niobate crystals for photonic applications are reviewed, acting on stoichiometry, sample structure, doping and domain structure of the crystals, these properties are governed, and can be taylored for each specific application.
Abstract: In this paper the most important properties of lithium niobate crystals for photonic applications are reviewed. We will summarize how acting on the stoichiometry, sample structure, doping and domain structure of the crystals, these properties are governed, and can be taylored for each specific application. Finally we present a review of photonic applications in a wide spectrum of fields as lasers and non-linear optics, optical communications, optical memories, and diffractive optics.
557 citations
TL;DR: 3D photonic crystals that are particularly suited for optical device integration using a lithographic layer-by-layer approach are presented and optical measurements show they have resonant signatures around telecommunications wavelengths.
Abstract: Photonic crystals1,2,3 offer unprecedented opportunities for miniaturization and integration of optical devices. They also exhibit a variety of new physical phenomena, including suppression or enhancement of spontaneous emission, low-threshold lasing, and quantum information processing4. Various techniques for the fabrication of three-dimensional (3D) photonic crystals—such as silicon micromachining5, wafer fusion bonding6, holographic lithography7, self-assembly8,9, angled-etching10, micromanipulation11, glancing-angle deposition12 and auto-cloning13,14—have been proposed and demonstrated with different levels of success. However, a critical step towards the fabrication of functional 3D devices, that is, the incorporation of microcavities or waveguides in a controllable way, has not been achieved at optical wavelengths. Here we present the fabrication of 3D photonic crystals that are particularly suited for optical device integration using a lithographic layer-by-layer approach15. Point-defect microcavities are introduced during the fabrication process and optical measurements show they have resonant signatures around telecommunications wavelengths (1.3–1.5 µm). Measurements of reflectance and transmittance at near-infrared are in good agreement with numerical simulations.
515 citations
TL;DR: By measuring the resonant wavelength of a two-dimensional photonic crystal microcavity, a time-resolved sensing capability is demonstrated that can detect the change in refractive index of 0.002.
Abstract: We report an experimental demonstration of an ultracompact biochemical sensor based on a two-dimensional photonic crystal microcavity. The microcavity, fabricated on a silicon-on-insulator substrate, is designed to have a resonant wavelength (λ) near 1.5 µm. The transmission spectrum of the sensor is measured with different ambient refractive indices ranging from n=1.0 to n=1.5. From observation of the shift in resonant wavelength, a change in ambient refractive index of Δn=0.002 is readily apparent. The correspondence between absolute refractive index and resonant wavelength agrees with numerical calculation to within 4% accuracy. The evaporation of water in a 5% glycerol mixture is also used to demonstrate the capability for in situ time-resolved sensing.
454 citations
TL;DR: The design, fabrication, and measurement of photonic-band-gap waveguides, resonators and their coupled elements in two-dimensional photonic crystal (PhC) slabs have been investigated and a large group delay is observed by time-domain measurement.
Abstract: The design, fabrication, and measurement of photonic-band-gap (PBG) waveguides, resonators and their coupled elements in two-dimensional photonic crystal (PhC) slabs have been investigated. We have studied various loss mechanisms in PBG waveguides and have achieved a very low propagation loss (~1 dB/mm). For these waveguides, we have observed a large group delay (>100 ps) by time-domain measurement. As regards PBG resonators, we realize very high-Q and small volume resonators in PhC slabs by appropriate design. Finally, we demonstrate various forms of coupled elements of waveguides and resonators: 2-port resonant-tunneling transmission devices, 4-port channel-drop devices using the slow light mode, and 3-port channel-drop devices using the resonant-tunneling process.
451 citations
TL;DR: A new all-optical mechanism that can compress the bandwidth of light pulses to absolute zero, and bring them to a complete stop, is introduced and demonstrated by finite-difference time-domain simulations of an implementation in photonic crystals.
Abstract: We introduce a new all-optical mechanism that can compress the bandwidth of light pulses to absolute zero, and bring them to a complete stop. The mechanism can be realized in a system consisting of a waveguide side coupled to tunable resonators, which generates a photonic band structure that represents a classical analogue of the electromagnetically induced transparency. The same system can also achieve a time-reversal operation. We demonstrate the operation of such a system by finite-difference time-domain simulations of an implementation in photonic crystals.
23 Aug 2004
TL;DR: Experimental studies of gas sensing using air-guiding photonic bandgap fibers using standard single mode fibers for ease of use and improved stability are reported on.
Abstract: We report on experimental studies of gas sensing using air-guiding photonic bandgap fibers. The photonic bandgap fibers have at one end been spliced to standard single mode fibers for ease of use and improved stability
TL;DR: In this article, an approach for guiding and manipulating light on sub-wavelength scales using active nanowire waveguides and devices is presented. But the approach is limited to the case of light propagation.
Abstract: We report an approach for guiding and manipulating light on sub-wavelength scales using active nanowire waveguides and devices. Quantitative studies of cadmium sulfide (CdS) nanowire structures show that light propagation takes place with only moderate losses through sharp and even acute angle bends. In addition, measurements demonstrate that efficient injection into and modulation of light through nanowire waveguides are achievable in active devices. The ability to inject, guide, and manipulate light on a sub-wavelength scale using nanowire components that can be assembled into integrated structures represents a promising pathway towards integrated nanoscale photonic systems.
TL;DR: In this article, a triangular lattice photonic crystal is formed by dry etching into the top GaN layer, and the chosen lattice spacing causes Bragg scattering of guided modes out of the LED, increasing the extraction efficiency.
Abstract: Electrical operation of InGaN/GaN quantum-well heterostructure photonic crystal light-emitting diodes (PXLEDs) is demonstrated. A triangular lattice photonic crystal is formed by dry etching into the top GaN layer. Light absorption from the metal contact is minimized because the top GaN layers are engineered to provide lateral current spreading, allowing carrier recombination proximal to the photonic crystal yet displaced from the metal contact. The chosen lattice spacing for the photonic crystal causes Bragg scattering of guided modes out of the LED, increasing the extraction efficiency. The far-field radiation patterns of the PXLEDs are heavily modified and display increased radiance, up to ∼1.5 times brighter compared to similar LEDs without the photonic crystal.
TL;DR: A collection of robust complete three-dimensional dielectric photonic-bandgap structures for the visible and near-infrared regimes based on the diamond morphology together with their specific fabrication techniques are surveyed.
Abstract: Certain periodic dielectric structures can prohibit the propagation of light for all directions within a frequency range. These 'photonic crystals' allow researchers to modify the interaction between electromagnetic fields and dielectric media from radio to optical wavelengths. Their technological potential, such as the inhibition of spontaneous emission, enhancement of semiconductor lasers, and integration and miniaturization of optical components, makes the search for an easy-to-craft photonic crystal with a large bandgap a major field of study. This progress article surveys a collection of robust complete three-dimensional dielectric photonic-bandgap structures for the visible and near-infrared regimes based on the diamond morphology together with their specific fabrication techniques. The basic origin of the complete photonic bandgap for the 'champion' diamond morphology is described in terms of dielectric modulations along principal directions. Progress in three-dimensional interference lithography for fabrication of near-champion diamond-based structures is also discussed.
TL;DR: In this paper, a photonic crystal lattice structure having a defect defines a suitable geometry for such a cavity (1000) and the analyte is introduced directly into a high optical field of the cavity (1002).
Abstract: A system, method and apparatus provide the ability to detect a chemical in an analyte. To detect the chemical, the invention utilizes a laser having an open cavity. A photonic crystal lattice structure having a defect defines a suitable geometry for such a cavity (1000). The analyte is introduced directly into a high optical field of the cavity (1002). Thereafter, the cavity is pumped (1004) and an emission from the laser is used to detect the presence of the chemical (1006) in the analyte.
02 Jul 2004
TL;DR: In this paper, the authors describe the properties of electromagnetic wave propagation in photonic band gap (PBG) structures and provide a detailed analysis of the electromagnetic properties of the system prior to fabrication.
Abstract: Nanotechnology is a scientific frontier with enormous possibilities. Reducing the size of objects to nanometer scale to physically manipulate the electronic or structural properties offers a fabrication challenge with a large payoff. Nanophotonics is a subfleld of nanotechnology and a part of nanophotonics includes photonic band gap structures, which manipulate the properties of light to enable new applications by periodically modulating the relative permittivity. In photonic band gap (PBG) structures, the electromagnetic properties of materials, such as the electromagnetic density of states, phase, group velocities, signal velocities, field confinement, and field polarization are precisely controlled. The size scale of interest in PBG structures is typically of the order of a wavelength, which is not quite as demanding as required to observe quantum confinement effects in electronic materials. Nevertheless, photonic devices designed with nanophotonic technology enable new technology for devices and applications in sensing, characterization, and fabrication.
Even though PBG photonic devices are complex and the fabrication is often expensive, rapid progress on PBG structures has been possible because of the development of powerful numerical computation tools that provide a detailed analysis of the electromagnetic properties of the system prior to fabrication. To design photonic devices we use a variety of computational techniques that help in evaluating performance.
Several books have already been written about the optical properties of PBGs. A classic book on ID periodic structures was written by Brillouin. Yariv and Yeh's book is an excellent resource on many aspects of periodic optical media. Recent books devoted to the subject include the books by Joannopoulos et al., the very thorough book by Sakoda, and a recent book on nonlinear optics of PBGs by Slusher and Eggleton that features results of several researchers who have contributed to the subject. In addition, many good articles on PBG structures can be found in special issues or in summer school proceedings.
Numerical approaches are available to completely describe the properties of electromagnetic wave propagation in PBG structures. Three methods are of general use; they are the plane wave, the transfer matrix, and the finite-difference time-domain (FDTD) methods. The results of the plane wave method with the latter two are to some degree complementary, as is demonstrated and discussed later in this chapter.
Analytical methods are also available and have been especially useful for 1D systems. For instance, the development of coupled-mode equations for propagation by using multiple scales or slowly varying amplitude methods has given researchers powerful tools for studying nonlinear effects and designing new electro-optic (EO) devices, such as tunable optical sources from the ultraviolet to the terahertz regime, EO modulators, and a new generation of sensitive bio/chem sensors.
TL;DR: An air-clad large-core single-transverse-mode ytterbium-doped photonic crystal fiber with a mode-field-diameter of 35 microm allowing for the frequency up-conversion of these pulses using narrow-bandwidth phase matched nonlinear crystals.
Abstract: We report on an air-clad large-core single-transverse-mode ytterbium-doped photonic crystal fiber with a mode-field-diameter of 35 µm, corresponding to a mode-field-area of ~1000 µm2. In a first experiment this fiber is used to amplify 10-ps pulses to a peak power of 60 kW without significant spectral broadening due to self-phase modulation allowing for the frequency up-conversion of these pulses using narrow-bandwidth phase-matched nonlinear crystals.
TL;DR: Experiments show the first experimental evidence of negative refraction at telecommunication wavelengths by a two-dimensional photonic crystal field by chemically assisted ion beam etching in the InP-based low-index constrast system.
Abstract: We report on the first experimental evidence of negative refraction at telecommunication wavelengths by a two-dimensional photonic crystal field. Samples were fabricated by chemically assisted ion beam etching in the InP-based low-index constrast system. Experiments of beam imaging and light collection show light focusing by the photonic crystal field. Finite-difference time-domain simulations confirm that the observed focusing is due to negative refraction in the photonic crystal area.
16 May 2004
TL;DR: In this paper, 3D photonic crystals with light-emitters and point-defects are fabricated and investigated, and it is experimentally shown that light emission is suppressed at the complete crystal parts, while cavity modes are successfully observed at the defect parts.
Abstract: 3D photonic crystals with light-emitters and point-defects are fabricated and investigated. It is experimentally shown that light-emission is suppressed at the complete crystal parts, while cavity modes are successfully observed at the defect parts.
TL;DR: In this paper, the photonic crystals (PCs) were used for enhancement of blue and UV optical power output in III-nitride light emitting diodes (LEDs) under current injection.
Abstract: We present results on enhancement of 460 nm blue and 340 nm UV optical power output in III-nitride light emitting diodes (LEDs) using photonic crystals (PCs) under current injection. Triangular arrays of the PCs with diameter/periodicity of 300/700 nm were patterned using electron-beam lithography and inductively coupled plasma dry etching. The total power at 20 mA of 300×300 μm2 unpackaged LED chips revealed an increase by 63% and 95% for the blue and UV LEDs, respectively, as a result of the PC formation. Possible ways for further improving enhancement of light extraction using PCs are discussed.
TL;DR: In this article, the optical structure of a representative diatom, Coscinodiscus granii, was analyzed and it was shown that light can be coupled into the waveguide and that there are some photonic resonances in the visible spectral range.
Abstract: We present an analysis of the optical structure of a representative diatom, Coscinodiscus granii. The silica cell wall can be regarded as a photonic crystal slab waveguide with moderate refractive-index contrast. In a cell, at least two different patterns are found: a hexagonal array of pores with a large lattice constant in the valve, and a square array of holes with a small lattice constant in the girdle. It is demonstrated that light can be coupled into the waveguide and that there are some photonic resonances in the visible spectral range, which have been determined by band-structure calculations.
Proceedings Article•
01 Jan 2004
TL;DR: Three-dimensional photonic crystals containing artificial point defects have been fabricated to emit light at optical communications wavelengths by stacking 0.7-micrometer-period gallium arsenide striped layers resulting in a 3D “woodpile” photonic crystal.
TL;DR: In this paper, a tunable light switch using a photonic crystal fiber filled with nematic liquid crystal is demonstrated, where the original band-gap-guiding fiber structure was transformed to a total internal reflection-guided photonic-crystal fiber by filling liquid crystal into the air core and cladding air holes.
Abstract: Tunable light switch using a photonic crystal fiber filled with nematic liquid crystal is demonstrated. The original band-gap-guiding fiber structure was transformed to a total internal reflection-guiding photonic crystal fiber by filling liquid crystal into the air core and cladding air holes. By applying external voltage to the liquid-crystal-filled fiber, we have demonstrated an electrically tunable fiber-optical switch with over 30dB attenuation at 60Vrms for a He-Ne laser beam. This liquid-crystal-filled photonic crystal fiber will find useful applications in fiber-optic communication systems.
TL;DR: A robust nanosecond photonic crystal switching material by using poly(N-isopropylacrylamide) (PNIPAM) nanogel colloidal particles that self-assemble into crystalline colloidal arrays (CCAs) that permits the individual embedded nanogels PNIPAM particles to coherently and synchronously undergo their thermally induced volume phase transitions.
Abstract: We developed a robust nanosecond photonic crystal switching material by using poly(N-isopropylacrylamide) (PNIPAM) nanogel colloidal particles that self-assemble into crystalline colloidal arrays (CCAs). The CCA was polymerized into a loose-knit hydrogel which permits the individual embedded nanogel PNIPAM particles to coherently and synchronously undergo their thermally induced volume phase transitions. A laser T-jump from 30 to 35 °C actuates the nanogel particle shrinkage; the resulting increased diffraction decreases light transmission within 900 ns. Additional transmission decreases occur with characteristic times of 19 and 130 ns. Individual NIPAM sphere volume switching occurs in the ∼100 ns time regime. These nanogel nanosecond phenomena may be useful in the design of fast photonic crystal switches and optical limiting materials. Smaller nanogels will show even faster volume phase transitions.
TL;DR: In this article, the dispersion relation of electromagnetic waves in one-dimensional plasma photonic crystals is studied, and the frequency gap becomes larger with the increase of the plasma density as well as plasma width.
Abstract: The dispersion relation of electromagnetic waves in one-dimensional plasma photonic crystals is studied. The plasma photonic crystal is a periodic array composed of alternating thin plasma and dielectric material. The dispersion relation is obtained by solving a Maxwell wave equation using a method analogous to Kronig-Penny’s problem in quantum mechanics, and it is found that the frequency gap and cut-off appear in the dispersion relation. The frequency gap is shown to become larger with the increase of the plasma density as well as plasma width.
TL;DR: It is demonstrated that highly efficient evanescent-wave detection of fluorophore-labeled biomolecules in aqueous solutions positioned in the air holes of the microstructured part of a photonic crystal fiber even at wavelengths in the visible range is demonstrated.
Abstract: We demonstrate highly efficient evanescent-wave detection of fluorophore-labeled biomolecules in aqueous solutions positioned in the air holes of the microstructured part of a photonic crystal fiber. The air-suspended silica structures located between three neighboring air holes in the cladding crystal guide light with a large fraction of the optical field penetrating into the sample even at wavelengths in the visible range. An effective interaction length of several centimeters is obtained when a sample volume of less than 1 µL is used.
TL;DR: Woodpile photonic crystal structures fabricated in organic-inorganic hybrid polymers (Ormocers) and investigation of their optical properties are reported.
Abstract: Two-photon polymerization (2PP) is a powerful technique for the fabrication of 3D micro- and submicro-structures. By applying laser powers that are only slightly above the polymerization threshold, 3D structuring of photosensitive materials with a resolution down to 100 nm can be realized. Here we report on woodpile photonic crystal structures fabricated in organic-inorganic hybrid polymers (Ormocers) and investigation of their optical properties. The fabricated crystals possess a photonic band gap in the near infrared spectral region. The polymeric woodpile structures can be used as templates for the fabrication of highly refractive TiO2 replicas. First results in this direction are presented.
TL;DR: An all-optical modulator is demonstrated, which utilizes a pulsed 532nm laser to modulate the spectral position of the bandgaps in a photonic crystal fiber infiltrated with a dye-doped nematic liquid crystal.
Abstract: Photonic crystal fibers (PCFs) have attracted significant attention during the last years and much research has been devoted to develop fiber designs for various applications, hereunder tunable fiber devices. Recently, thermally and electrically tunable PCF devices based on liquid crystals (LCs) have been demonstrated. However, optical tuning of the LC PCF has until now not been demonstrated. Here we demonstrate an all-optical modulator, which utilizes a pulsed 532nm laser to modulate the spectral position of the bandgaps in a photonic crystal fiber infiltrated with a dye-doped nematic liquid crystal. We demonstrate a modulation frequency of 2kHz for a moderate pump power of 2–3mW and describe two pump pulse regimes in which there is an order of magnitude difference between the decay times.
TL;DR: Exceptional transmission through a photonic crystal waveguide Z-bend is obtained using this inverse design strategy and a large low loss bandwidth of more than 200 nm for the bandgap polarization is experimentally confirmed.
Abstract: Topology optimization is used to design a planar photonic crystal waveguide component resulting in significantly enhanced functionality. Exceptional transmission through a photonic crystal waveguide Z-bend is obtained using this inverse design strategy. The design has been realized in a silicon-on-insulator based photonic crystal waveguide. A large low loss bandwidth of more than 200 nm for the TE polarization is experimentally confirmed.