Kinds Of Microcavities Research Articles

Stimulated Brillouin Scattering by Dual Lasers Pumping in WGM Microcavities

Stimulated Brillouin scattering (SBS) is experimental investigated in several hundred microns in diameter microspheres with a little eccentricity by melting a fiber tip in a fusing splicer. Fourth order cascaded SBS at C-band (∼1540 nm) with 27 mW can be achieved with the abundant and high Q modes in the microspheres. This kind of microcavity also supports high Q modes in O-band (∼1320 nm) and second order SBS has been observed. In addition, SBS is also investigated by pumping-heating method with a heating laser at O-band and a pumping laser at C-band. We achieved a tunable SBS with high flexibility on the wavelength, thus the pumping laser can be set at a specified wavelength assisted by the heating laser. This method provides us a new approach for generation of SBS without tuning the pumping laser wavelength and will benefit various applications.

Optical transmission characteristics of multi-band triangular-lattice photonic crystal coupling cavity waveguide based on annular microcavity

The light localization characteristics of the near-infrared triangular-lattice photonic crystal annular microcavity are studied theoretically in this paper. The photonic crystal has a lattice constant of <i>a</i>=540 and it is composed of silicon rods each with a radius of <i>r</i>=135 immersed in air background. The two kinds of annular microcavities are obtained by removing 12 silicon rods which are located respectively at a distance of 2a and at a distance of √<span style="border-top:1px solid; padding-top:0px;">3</span><i>a</i> to the central rod. Five resonant wavelengths and the corresponding eigen mode profiles of the microcavity are studied. A coupled resonant optical waveguide is formed by integrating the microcavities with a periodic length of 7<i>a</i> in space. The group velocity of light beam propagation within multiple guiding bands are analyzed by the tight-binding approximation method. The maximum and minimum velocity of 0.0028<i>c</i> and 0.00082<i>c</i> are obtained, where <i>c</i> is the light velocity in vacuum. The light transmittance values and spatial steady distributions of the electric field's amplitude through the structure at several wavelengths within the guiding bands are studied by the finite-difference time-domain method. The results are consistent with that calculated by the plane wave expand method. Interleaving circular microcavities perpendicular to the direction of optical transmission at a lateral distance of 2√<span style="border-top:1px solid; padding-top:0px;">3</span><i>a</i>, the coupling region between the adjacent microcavities is changed, the difference in group velocity between guiding bands apparently decreases and the transmittance values of two frequency bands are enhanced.<br/>Keeping the size of silicon rods unchanged, two kinds of microcavities are constructed by removing the six rods with the distances of 2<i>a</i> and √<span style="border-top:1px solid; padding-top:0px;">3</span><i>a</i> from the center of the central silicon rod, respectively. The resonant wavelengths supported by the above two microcavities are studied. Two coupled-resonant optical waveguides with a periodic length of 7<i>a</i> are proposed. Connecting these two coupled cavity optical waveguides with the W1-typed input/output waveguides, the selecting and sharing function of guiding band are finally achieved for wavelengths within different frequency bands. Keeping the group velocity slowing down, a maximum value of one guiding band reaches 0.00047<i>c</i>.

Magnetic Response Property of Magnetic Fluid Photonic Crystal Microcavity

A kind of microcavity using magnetic fluid photonic crystal was presented,and its forming process was explained theoretically. Then the sensing property was studied,and the transmission characteristic was computed. The magnetic response properties of the proposed structure with the thickness of 6 μm and 0. 94 μm were analyzed respectively. It was found that the central wavelength of resonance peak would be blue-shifted about 4. 130 μm and 0. 076 μm.The maximum sensitivity was 243 nm / m T and 3. 8 nm / m T respectively. The sensor system exhibited the advantages of easy tuning,simple formation and high sensitivity,which would provide a newidea for optical sensor.

A Single Photon Source Model Based On Quantum Dot And Microcavity

We report a single photon source model which consists on InAs/GaAs pyramidal quantum dot (QD) model based on effective mass theory to calculate the emitted photons energies. We study the choice of geometrics parameters of QD to obtain emission at 1550 nm. This quantum dot must be embedded on a microcavity to improve the live time of photon at 1550 nm and inhibit the others photons to increase the probability to obtain only one emitted photon. We present two kinds of microcavities; the first based on two dimensional photonic crystal over GaAs, we study the geometric parameters choice to obtain a height density of mode (DOM) at 1550 nm; the second microcavity is based on microdisk structure over GaAs we evaluate the impact of radius variation to obtain whispering-gallery mode at 1550 nm. This study can serve for the conception of new quantum communications protocols.

Excimer laser micromachining for 3D microstructure

A new 3D micromachining method, called Hole Area Modulation (HAM), has been introduced to enhance the current micromachining technology. In this method, information on the machining depth is converted to the sizes of holes on the mask. The machining is carried out with a simple 2D movement of the workpiece or the mask. This method can be applied for machining various kinds of microcavities in various materials. In this paper, a mathematical model for excimer laser micromachining based on HAM and determination of the optimal laser ablation conditions (hole diameter, step size, mask movement velocity, etc.) are described. The simulation and experiment of the HAM-based laser ablation were carried out successfully to create microlens.

Excimer laser micromachining for 3D microstructure

A new 3D micromachining method, called H ole A rea M odulation (HAM), has been introduced to enhance the current micromachining technology. In this method, information on the machining depth is converted to the sizes of holes on the mask. The machining is carried out with a simple 2D movement of the workpiece or the mask. This method can be applied for machining various kinds of microcavities in various materials. In this paper, a mathematical model for excimer laser micromachining based on HAM and determination of the optimal laser ablation conditions (hole diameter, step size, mask movement velocity, etc.) are described. The simulation and experiment of the HAM-based laser ablation were carried out successfully to create microlens.

Spontaneous emission properties of organic film in plane optical microcavity

The spontaneous emission properties of a single layer organic film in plane optical microcavities were studied. Optical microcavity was formed by a Tris(8-quinolinolato) aluminium (Alq) film sandwiched between a distributed Bragg reflector (DBR) and a Ag metallic reflector. Two kinds of microcavities were devised by using a different DBR structure. Compared with a Alq film, significantly spectral narrowing and intensity enhancement was observed in the two microcavities, which is attributed to the microcavity effect. The spectra characteristics of the two microcavities showed that the structure of DBR has much influence on the emission properties of a microcavity.

A New Method for Three Dimensional Excimer Laser Micromachining, Hole Area Modulation (HAM)

A new excimer laser system configuration for three dimensional (3D) micromachining, called Hole Area Modulation (HAM) method, is proposed and the feasibility of the system is experimentally confirmed. In this method, information on the depth of machining is converted to the sizes of small holes in the mask. The machining is carried out with a simple 2D movement of the workpiece. Since the total area of the targeted cavity is machined simultaneously, a 2.5-μm-deep, 800μm × 1600μm 3D cavity was machined in about 5s. This method can be applied for machining various kinds of microcavities in various materials. Owing to the short machining time, the fabrication of a mold with repeated shapes, for example a mold for a microlens array, will be a good application in the future.