The transmission property and localization of electromagnetic waves in defect free dodecagonal quasiperiodic photonic crystals (QPCs) are studied. simulation total energy flow the density states show that QPC has a gap for TM polarized waves. However, different from periodic crystals, with certain frequencies localized at some special regions inside perfect QPC. A corresponding experiment microwave region confirms phenomenon. It is believed occurrence modes QPCs can be attributed to...

Strong coupling between a cavity and transition dipole moments in emitters leads to vacuum Rabi splitting. Researchers have not reported strong single emitter dielectric at room temperature until now. In this study, we investigated the photoluminescence (PL) spectra of colloidal quantum dots on surface SiO2/Si material various collection angles temperature. We measured corresponding reflection for compared them with PL spectra. observed spectral splitting regarded it as material. Upper...

For colloidal quantum dots, the ongoing biggest problem is their fluorescence blinking. Until now, there no generally accepted model for this Here, two-photon excited from CdSe/ZnS nanocrystals on silicon nitride photonic crystals studied using a femtosecond laser. From analysis of spectra and decay processes, most relative trion efficiency larger than 10%, largest reaches 46.7%. The enhance emission nanocrystals, where enhancement due to coupling leaky mode crystal slab. Moreover,...

The interaction between light and matter has always been the focus of quantum science, realization truly strong coupling an exciton optical cavity is a basis information systems. As special semiconductor material, colloidal dots have fascinating properties. In this study, photoluminescence spectra are measured at different collection angles in microcavities based on hybrid refractive-index waveguides. photon bound states continuum found low–high–low waveguides appropriate waveguide width...

We explore an easy method for preparation of a hybrid device photonic crystal InGaN/GaN quantum well (QW) and colloidal dots using conventional photolithography. It is demonstrated from electroluminescence spectra that Förster resonance energy transfer takes place efficiently between the QW CdSe/ZnS dots. From photoluminescence decay QW, largest efficiency GaN measured as 88% corresponding Förster-resonance-energy-transfer fraction reached 42%. An approach explored to realize highly...

Light extraction effects of a photonic crystal slab with micrometer scale lattice constant are studied. A GaN light emitting diode (LED) is fabricated. The and the enhancement mechanism investigated. From theoretical analysis, it found that characteristics LED emission modulated by slab. Experimental results show intensity enhanced 38% due to guide mode extracting crystal.

A high quality-factor (Q) cavity based on a one-dimensional (1D) photonic crystal with gradated elliptical holes was designed using FDTD simulation. Different gradient profiles of the mirror were found to correspond different Q-values cavities. simple strategy is proposed construct high-Q cavities by an S-shaped profile for holes' minor axes, such as cosine function or Gaussian function. Using strategy, Q value exceeding two million obtained only ten in cavity.

A two-dimensional photonic crystal coupled-cavity waveguide is designed and optimized, the transmission spectrum calculated by using finite-difference time-domain method, group velocity of c/1856 obtained. To our knowledge, this value lowest in a from its so far. The result confirmed band structure plane wave expansion it found that modes are accordance with those method. mechanism slow light analysed.

Abstract In this study, the evolution spectrum and emission dynamics of atoms in a defect-free quasiperiodic photonic crystal are studied. Quasiperiodic have advantages over periodic terms abundant strong localized modes due to self-approximation structures crystal. The exhibit extremely large local density states high-quality factors frequencies do not depend on polarization position particular area crystals. Due crystal, coupling between atom mode can easily occur. Correspondingly,...

In this study, the two-photon excited fluorescence spectra from cadmium selenide quantum dots (QDs) on a silicon nitride photonic crystal (PhC) membrane under femtosecond laser irradiation were investigated. These can be fit to tri-Gaussian function in which one component is negative amplitude, and Gaussian components with positive amplitude are assigned exciton emission charged-exciton that absorption surface recombination. The enhance and, at same time, also Both recombination related...

The dynamics of spontaneous emission from GaAs slabs with photonic crystals etched into them are investigated both theoretically and experimentally. It is found that the intensity decreases significantly shorten lifetime emission. mechanics enhancement reduction analyzed by considering surface recombination GaAs. measured calculated lifetimes agree at a velocity 1.88×105cm∕s.

The defect modes of a two-dimensional quasiperiodic photonic crystal (QPC) with defects are studied. It is found that if the possess same rotational symmetry, resonant frequencies identical. On other hand, uncoupled exist when field symmetry different from external exciting waves. A corresponding experiment in microwave region confirms phenomenon.

Abstract The interaction between high-intensity ultrashort optical pulses and materials has led to a number of fascinating phenomena, including Rabi flopping self-induced transparency. Until now, there have been few reports on coherent pulse propagation reshaping in semiconductor materials. Here we investigate splitting colloidal quantum dots with Fabry-Perot cavity SU8/Si. phenomenon is monitored via the pump-probe differential reflection spectroscopy. A high excitation power reshapes...

We investigate two-photon excited fluorescence from CdSe quantum dots with a center-emitting wavelength of 655 nm on SiN photonic crystals. find that is enhanced by more than 1 order magnitude in the vertical direction when crystal used compared to spectra absence The spectrum observed shift blue without

Two-photon excited fluorescence (TPEF) under continuous-wave excitation from silicon particles produced by a pulsed laser is investigated. Spectra and images of TPEF are studied different intensities operation modes (continuous wave or pulse). It found that the photoluminescence depends superlinearly on intensity spectral shape peaks vary with particles. The above phenomena show nonlinear behavior particles, stimulated emission possible process.

An electrically driven, single-longitudinal-mode GaAs based photonic crystal (PC) ridge waveguide (RWG) laser emitting at around 850 nm is demonstrated. The lasing characteristic achieved by introducing the PC to RWG laser. triangle etched on both sides of photolithography and inductive coupled plasma (ICP) etching. spectra lasers with without are studied, result shows that purifies longitudinal mode. power per facet versus current current-voltage characteristics have also been studied compared.