Photonic Crystal Films with High Refractive Index Contrast

Müller, Manfred; Zentel, Rudolf; Maka, T.; Romanov, S. G.; Torres, C. M. Sotomayor

doi:10.1002/1521-4095(200010)12:20<1499::aid-adma1499>3.3.co;2-d

Cited by 65 publications

(98 citation statements)

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“…Tin disulfide has a refractive index of 3.2 (at 700 nm) and is transparent above its absorption edge at 550 nm. [24] Our theoretical calculations show that, for certain sets of parameters, a complete bandgap opens up between the eighth and the ninth band of the DIOPC. In the following, we will show that it is possible to completely open and close this bandgap by shifting the position of the silica spheres within the pores.…”

Section: Pbg Switchingmentioning

confidence: 85%

See 1 more Smart Citation

Double‐Inverse‐Opal Photonic Crystals: The Route to Photonic Bandgap Switching

Ruhl¹,

Spahn²,

Hermann

et al. 2006

Adv Funct Materials

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Photonic crystals with a complete bandgap can stop the propagation of light of a certain frequency in all directions. We introduce double‐inverse‐opal photonic crystals (DIOPCs) as a new kind of optical switch. In the DIOPC, a movable, weakly scattering sphere is embedded within each pore of the inverse‐opal photonic crystal lattice. Switching between a diffusive reflector and a photonic crystal environment is experimentally demonstrated. Theory shows that a complete bandgap can be realized that can be opened or closed by moving the spheres. This functionality opens up new possibilities for the control of light emission and propagation. The close link and interaction between the chemical synthesis and the computational design and analysis underlines the interdisciplinary focus of this report.

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Section: Pbg Switchingmentioning

confidence: 85%

“…[24] The PMMA layer of the core/shell particles was removed by calcination in air at 240°C, yielding the DIOPC structure. The temperature needed to be controlled precisely since a b c Figure 1.…”

Section: Fabricationmentioning

confidence: 99%

Double‐Inverse‐Opal Photonic Crystals: The Route to Photonic Bandgap Switching

Ruhl¹,

Spahn²,

Hermann

et al. 2006

Adv Funct Materials

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“…This method can be used for the synthesis of the macroporous semiconductors Si [105±107], Ge [108], and SnS 2 [109,110], which as bulk materials have the extremely high refractive index that is required for the formation of a complete PBG. Absorption of semiconductors in the visible region, however, generally limits the PBG to infrared wavelengths.…”

Section: Chemical Vapor Depositionmentioning

confidence: 99%

“…Macroporous SnS 2 is prepared by room temperature CVD around PMMA colloidal crystals by employing SnCl 4 vapor and H 2 S gas as precursors [109,110]. Removal of the template by dissolving in THF produces macroporous SnS 2 .…”

Section: Chemical Vapor Depositionmentioning

confidence: 99%

3D Ordered Macroporous Materials

Schroden

Stein

2003

Colloids and Colloid Assemblies

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IntroductionMaterials exhibiting a uniform arrangement of pores offer a wide variety of applications that are based on both the chemical properties of the solid matrix and properties specific to the pore size and arrangement. The International Union of Pure and Applied Chemistry (IUPAC) has classified porous materials into three distinct categories according to their pore diameters [1]. ªMicroporesº are those with diameters less than 2 nm, ªmesoporesº range from 2 to 50 nm, and ªmacro-poresº are greater than 50 nm in diameter [1]. Interest in the synthetic creation of ordered porous materials began with the desire to replicate or improve upon the unique properties that result from the crystalline microporous structure of natural zeolites. With small pore sizes, open frameworks, high specific surface areas, and extremely well-defined structures, zeolites have found commercial applications as adsorbents, molecular sieves, and size-or shape-selective catalysts [2]. However, zeolites are limited to applications involving small-molecule substrates. For chemical applications involving larger guest molecules, such as biological compounds or polymers, materials with larger pores are required.The development of laboratory techniques for the preparation of ordered porous materials with well-defined structures and pore sizes began in the 1950s with the creation of the first commercially significant synthetic zeolites, and has continued to the present [2]. The general procedure for the preparation of porous materials involves the use of sacrificial templates, space fillers, or structure directors around which a solid wall structure forms. Upon removal of the template by chemical or thermal methods, porous materials are produced. For zeolites, the sacrificial species is often a single molecule such as an alkyl-amine [2]. The size of the micropores of zeolites can be increased through the use of larger molecular templates, reaching a maximum pore size of approximately 2 nm [2]. While methods for preparing ordered microporous materials have been known for over fifty years, techniques for the fabrication of ordered materials with larger pores have only been developed since the early 1990s.A new era in porous materials synthesis began with the development of techniques based on the use of self-assembled molecular arrays, instead of single mol-465 15

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“…[ 11 ] A slight redshift in the refl ection dip with increasing fi lling factor is observed, indicating an increase in the refractive index with increasing fi lling factor, as expected. [ 12 ] High-effi ciency coupling close to 100%, which leads to the lowest refl ection, was achieved only in Comp.7. To the best of our knowledge, such a high coupling was only observed using a grating or prism as a coupler.…”

mentioning

confidence: 99%

An Omnidirectional Transparent Conducting‐Metal‐Based Plasmonic Nanocomposite

Elbahri

Hedayati²,

Chakravadhanula³

et al. 2011

Advanced Materials

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The task to produce a transparent metal, with conductivity comparable to indium tin oxide (ITO) while retaining high transparency through the visible region has so far proven to be challenging. In this regard, metal-polymer nanocomposites have traditionally been excluded from investigation due to their strong absorption and refl ection of visible light. Here, we present the fi rst transparent conducting metal (TCM) composed of a stack of a gold fi lm and a silver/polymer nanocomposite fabricated by sputtering on a glass substrate. In this plasmonic device, the refl ection is minimized by means of symmetric plasmonic coupling under impedance matching condition in the visible range. Additionally the magnetic optical resonance, which is induced by dipole-image interaction lowers the absorption and scattering of the whole structure. Since both phenomena occur in the same wavelength range, the optical transmission of the device is signifi cantly enhanced. The plasmonic metamaterial shows an omnidirectional optical transmission up to 80% in the visible wavelength range, which is comparable to that of ITO, and an electrical conductivity that is one order of magnitude higher than that of ITO.In the fi eld of plasmonics, much attention is paid to new approaches for the concentration and manipulation of light to improve the absorption and/or transmission of energy. [ 1 ] For instance, a combination of noble metal nanoparticles and a metal fi lm has been used to diminish the refl ection by plasmonic coupling. [ 2 ] Applying the same idea, recently a perfect absorber was realized with a structure consisting of a gold metal fi lm separated from gold nanoparticles with MgF 2 as an interlayer. [ 3 ] Other plasmonic devices, which show high absorbance, were fabricated by structuring a metal surface in different manners such as a nanostructure layer [ 4 ] or microcavities on the top surface. [ 5 ] Light propagation normal to the metal fi lm is an interesting issue. When the fi lm is optically thin, i.e., in the range of the skin depth, the energy transfer can be enhanced by the surface plasmon polariton (SPP) mode and super-resolution imaging can be achieved. [ 6 ] These unique features have generated the rapidly growing fi eld of SPP-based photonics or plasmonics. Plasmonics combines both the capacity of photonics and the miniaturization capability of electronics and is thus an outstanding candidate for future optoelectronic applications. [ 7 ] Transparent conductors (TCs), which are integral components in fl at panel displays, solar cells, and smart windows, deliver electrons to or collect them from the active part of the device while at the same time allowing visible photons to pass through relatively unimpeded. At present, ITO and other transparent conductive oxides (TCO) are used. Efforts to produce a transparent metal with conductivity superior to ITO that retains high transparency through the visible region has so far proved to be challenging. [ 8 ] Metal/polymer nanocomposites, which show some attractive optical propertie...

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Photonic Crystal Films with High Refractive Index Contrast

Cited by 65 publications

References 0 publications

Double‐Inverse‐Opal Photonic Crystals: The Route to Photonic Bandgap Switching

Double‐Inverse‐Opal Photonic Crystals: The Route to Photonic Bandgap Switching

3D Ordered Macroporous Materials

An Omnidirectional Transparent Conducting‐Metal‐Based Plasmonic Nanocomposite

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