Intrinsic molecular fluorescence from porphyrin molecules on Au(100) has been realized by using a nanoscale multimonolayer decoupling approach with nanoprobe excitation in the tunneling regime. The origin of luminescence is established observed well-defined vibrationally resolved spectra. fluoresce at low "turn-on" voltages for both bias polarities, suggesting an mechanism via hot electron injection either tip or substrate. excited decay radiatively through Franck-Condon pi(*)-pi transitions.

This letter describes the electrical control of structure and lasing in photonic bandgaps cholesteric liquid crystals (CLCs). Photoexcitation dye-doped CLC cells with a linearly polarized laser gives rise to emission at edge(s) chiral band gap. Applying voltages optically pumped enables reversible switching action as result structural changes

Nonlinear optical dendritic macromolecules, called azobenzene dendrons, were synthesized, and their conformational properties molecular nonlinear clarified by second-order measurement. The synthesized molecules modified introducing 1−15 numbers of branching units as the chromophore placing aliphatic chains at end chains. In these topologically complex molecules, each contributed coherently to macroscopic activity. first-order hyperpolarizability dendron having 15 chromophoric was measured be...

Saddle-shaped deformation of planar porphyrin molecules is accomplished by rotations four phenyl-based substituents, which results from optimum adsorption onto Au(111) surface. The nonplanar macrocyclic conformation clearly visualized using low-temperature scanning tunneling microscopy and confirmed molecular orbital calculations. Inside the supramolecular islands, we find that two different orientations porphyrins are randomly distributed. An orientational ordering obtained after short...

This letter describes the phototunable photonic bandgap of cholesteric liquid crystal (CLC) doped with a fluorescent dye to generate distributed feedback effect. Photoirradiation dye-doped CLC cell under UV light at 254 nm resulted in continuous changes chiral from 550 720 due photolysis reaction cholesteryl iodide embedded host. We showed that laser oscillation wavelength could be controlled wide range 610 700 by photoassisted adjustment bandgaps.

Abstract We propose a high efficiency apodized grating coupler with bottom reflector for silicon nitride photonic integrated circuits. The consists of stack alternate and dioxide quarter-wave films. design, fabrication optical characterization the couplers has been presented. measured fiber to detector insertion loss was −3.5 dB which corresponds peak coupling −1.75 dB. A 3 wavelength bandwidth 76.34 nm demonstrated 20-layer reflector. process is CMOS-compatible requires only single etching step.

Mirrorless laser emission from fluorescent dye-loaded anodic porous alumina with an ideally arranged hole array configuration is observed. The wavelength of the (see Figure) appears at edge photonic bandgap in two-dimensional that originates alumina, and can be tuned by changing geometrical structure alumina.

Abstract Electro‐optic side‐chain polymers have been synthesized by the post‐functionalization of methacrylate isocyanate with novel phenyl vinylene thiophene bridge (FTC) nonlinear optical chromophores. For this application, FTC‐based chromophores were modified in their electronic donor structure, exhibiting much larger molecular hyperpolarizabilities compared benchmark FTC. Of these new chromophores, absorption spectra, hyper‐Rayleigh scattering experiment, and thermal analysis carried out...

An electro-optic (EO) polymer waveguide using an ultra-thin silicon hybrid has been designed and fabricated. The core the thickness of 50 nm a width 5 μm. was completed after covering cladding with high temperature stable EO polymer. We have demonstrated low half-wavelength voltage 0.9 V at wavelength 1.55 μm by Mach-Zehnder interference modulator TM mode operation. measured modulation corresponded to effective in-device coefficient 165 pm/V. By utilizing traveling-wave electrode on...

Abstract The gap between the performance of optoelectronic components and demands fiber-optic communications has narrowed significantly in recent decades. Yet, expansion data traffic remains substantial, with fiber-link speeds increases anticipated near future. Here, we demonstrate an ultra-high-speed electro-optic waveguide modulator constructed using a thin film lanthanum-modified lead zirconate titanate ferroelectric phase exhibiting strong Pockels effect. wide optical window; thus,...

Flexible and compact optical switch is important for communications. In this Letter, a thermo-optical with wavelength division (de)multiplexing (WDM) function has been proposed demonstrated experimentally. The comprised of 1 × 2 Bezier multimode interferometer (MMI) an angled (AMMI). separates 1490 1550 nm wavelengths realizes path reconfiguration simultaneously. device footprint 13.63 0.385 mm built on 2% refractive index difference silica platform. excess loss lower than 1.2 dB (the...

We propose and experimentally demonstrate a modulation technique, termed orthogonal chirp division multiplexing with index (OCDM-CIM), where partial chirps are deliberately unmodulated to reduce interference energy consumption. OCDM-CIM exhibits the combined advantages of rejection from chirp-spread spectrum in OCDM efficiency (EE) modulation, achieving an attractive trade-off among spectral (SE), EE, performance by flexibly controlling number active per subblock adapt different granularity...

The selective assembly of carboxyphenyl substituted porphyrins on the Au (111) surface has been studied using scanning tunneling microscopy. We find that conformational isomers are induced upon adsorption and selectively assembled into hydrogen-bonded supramolecular clusters or wires surface. conformation is attributed to coplanar intermolecular interactions between groups.

Micro-ring resonators have been widely utilized in silicon photonics. However they often exhibit a high sensitivity to ambient temperature fluctuations. In this letter, we demonstrated complementary metal–oxide–semiconductor compatible athermal micro-ring resonator made from titanium dioxide (TiO2) and nitride (SiNx). We exploited the negative thermo–optic coefficient of TiO2 counterbalance positive SiNx. By precise control over layer thickness, an condition remarkably consistent with...

As a consequence of the urgent demand for an electro-optic (EO) polymer modulator with elevated temperature stability, we have prepared selection EO polymers having glass transition temperatures up to 194°C. The measured half-wave voltage characteristics fabricated Mach-Zehnder interference modulators revealed excellent thermal resistance at 105°C approximately 2,000 hours. By utilizing traveling-wave electrodes on modulator, high-frequency response 10-40 GHz was evaluated under ascending...

In this work, we have demonstrated a hybrid TiO2–Si3N4 ring resonator with high-Q and temperature-insensitive resonance. The waveguide consists of thermo-optic positive Si3N4 slab negative TiO2 overcladding. layer has shallow ridge structure, which been designed to realize an athermal operation maintain low scattering loss. During the fabrication waveguide, there was no need utilize dry-etching process. method affords straightforward precise control over dimensions. As result, exhibits high...

Ultra-thin silicon and electro-optic (EO) polymer hybrid waveguide modulators have been designed fabricated. The consists of a core with thickness 30 nm width 2 μm. cladding is an EO polymer. Optical mode calculation reveals that 55% the optical field around extends into in TE mode. A Mach-Zehnder interferometer (MZI) modulator was prepared using common coplanar electrodes. measured half-wave voltage MZI 7 μm spacing 1.3 cm long electrodes 4.6 V at 1550 nm. evaluated coefficient 70 pm/V,...

We report on the first demonstration of long-term thermally stable silicon-organic hybrid (SOH) modulators in accordance with Telcordia standards high-temperature storage. The devices rely an organic electro-optic sidechain polymer a high glass transition temperature 172 {\deg}C. In our storage experiments at 85 {\deg}C, we find that activity converges to constant level after initial decay. If consider burn-in time 300 h, {\pi}-voltage increases average by less than 15 % if store for...

We prepared high-gain media for laser emission by using a conventional laser-dye (DCM) and dendrimer. A dendrimer can encapsulate the dye, therefore increase its concentration up to 9.0 mM with limited self-aggregation intermolecular quenching. The optical confinement is attributed gain guiding under excitation. spectrum clearly indicated periodic resonant modes though feedback was caused in an unusual way. Above lasing threshold, spectral linewidth became less than 0.1 nm. laser-dye-doped...

Abstract A methacrylate‐based crosslinking hyperbranced polymers have been synthesized through initiator‐fragment incorporation radical polymerization and used for the temperature stable electro‐optic (EO) polymer application. This consists of methyl methacrylate, 2‐metacryloxyethyl isocyanate, ethylene glycol dimethacrylate (EGDMA) monomers. The use EGDMA as a bifunctional unit resulted in solvent‐soluble hyperbranched chain, so that EO enhanced glass transition temperatures. phenyl...