61 results about "Mode volume" patented technology

The invention relates to a Bragg refractive waveguide edge transmitting semiconductor laser with a low horizontal divergence angle, wherein the P electrode of the laser is placed on the top face of a cover layer and is electrically connected onto the cover layer; the N electrode is positioned on the back face of a substrate and is electrically connected to the substrate; a center cavity is positioned between an upper waveguide layer and a lower waveguide layer; an active area is inserted in the center cavity; a Bragg refractive waveguide formed by periodically distributing a plurality of layers of N-doped materials with a high refractive index and a low refractive index is adopted in the lower waveguide layer on; and a Bragg refractive waveguide formed by periodically distributing a plurality of layers of P-doped materials with a high refractive index and a low refractive index is adopted in the upper waveguide layer. The Bragg refractive waveguide edge transmitting semiconductor laser with the low horizontal divergence angle has the advantages that: effects such as catastrophic damage, hole burning, electric heat overburning, beam filamentization and the like on the end face of the traditional edge transmitting semiconductor laser can be effectively improved, and the laser can realize the large mode-volume and stable single-transverse-mode work because of the great gain loss difference between a basic mode and a high-order mode, the full wave at half maximum (FWHM) of the transverse far-field divergence angle of the laser can reach below 10 DEG.

An optical device that comprises an input waveguide, an output waveguide, a high-Q resonant or photonic structure that generate slow light connected to the input waveguide and the output waveguide, and an interface, surface or mode volume modified with at least one material formed from a single molecule, an ordered aggregate of molecules or nanostructures. The optical device may include more than one input waveguide, output waveguide, high-Q resonant or photonic structure and interface, surface or mode volume. The high-Q resonant or photonic structure may comprise at least one selected from the group of: microspherical cavities, microtoroidal cavities, microring-cavities, photonic crystal defect cavities, fabry-perot cavities, photonic crystal waveguides. The ordered aggregate of molecules or nanostructures comprises at least one selected from the group of: organic or biological monolayers, biological complexes, cell membranes, bacterial membranes, virus assemblies, nanowire or nanotube assemblies, quantum-dot assemblies, one or more assemblies containing one or more rhodopsins, green fluorescence proteins, diarylethers, lipid bilayers, chloroplasts or components, mitochondria or components, cellular or bacterial organelles or components, bacterial S-layers, photochromic molecules. Further, the molecular aggregate may exhibit a photoinduced response.

A sensor for determining the presence or concentration of a target entity in a medium is described, and includes (a) an optical waveguide; (b) a microresonator optically coupled with the optical waveguide such that light within the optical waveguide induces a resonant mode within the microresonator at an equator region (or a mode volume); and (c) at least one plasmonic nanoparticle adsorbed onto a surface area of the microresonator within the equator region (or the mode volume) such that light inducing a resonant mode within the microresonator also causes a plasmonic resonance in the at least one plasmonic nanoparticle. Detection methods for using such sensors are also described. Finally, methods, involving the use of carousel forces, for fabricating such sensors are also described.

The invention provides a design method of a semiconductor diode double-end-pumped high-power UV laser, which comprises following steps: constituting a double-end-pumped laser crystal by using two semiconductor diodes; outputting a pumped beam with 808 nm; coupling the pumped beam by an aspherical optical coupling system and a lens to a laser crystal to generate a laser beam with 1064 nm; oscillating the laser beam in a resonant cavity consisting of five planar mirrors; modulating with Q switch; converting the modulated fundamental frequency light with 1,064 nm into a frequency-doubled light with 532 nm by a frequency-doubling crystal; mixing the unconverted fundament frequency light with 1,064 nm with the frequency-doubled light with 532 nm by a frequency-tripling crystal to obtain a UV laser with 355 nm; and outputting the UV laser from a surface of the frequency-tripling crystal cut by Brewster angle. According to the scheme, the laser cavity has the advantages of large mode volume, smaller laser spot at the frequency-doubling crystal, greatly reducing intracavity loss by cutting the frequency-tripling crystal with Brewster angle and high power laser output.

This invention discloses one mixture carbon fiber compound materials and its application, which comprises the following parts: spring mode volume as 500-650GPa carbon fiber A; spring mode as 360- 450GPa carbon fiber B and string intensity as 3200-5000MPa carbon fiber C. Due to used carbon fiber of high intensity and rigidity, it comprises good conductivity and piezoelectricity effect.

The invention discloses a method for improving collection efficiency of diamond NV color center fluorescence. The method comprises the following steps of forming an optical resonator by coupling a nano-diamond and a microsphere cavity based on the Purcell effect, integrating a microwave antenna thereon to prepare a microsphere cavity (200-500 microns) containing the nano-diamond, exciting the diamond NV color center to generate fluorescence by 532nm laser, and enhancing and collecting the fluorescence using a whispering wall mode such that the fluorescence generated by the diamond NV color center can be continuously circulated in the microsphere cavity, thereby establishing a strong light field and directly achieving the collection of fluorescence using the fiber connected to the sphere cavity. The method combines nano-diamond with optical microcavity with low requirements on preparation process, has the characteristics such as low cost, small mode volume and high energy density, realizes excitation and efficient collection of diamond NV color center fluorescence, and is expected to realize integrated application of NV color center based high sensitivity quantum sensors.

Ultrastable lasers serve as the backbone for advanced scientific experiments and enable atomic spectroscopy and laser interferometry at high levels of precision. But is not clear how to realize an ultrastable laser that is compact and portable for field use. An ultrastable laser source should be insensitive to both short- and long-term fluctuations in temperature, which ultimately broaden the laser linewidth and cause drift in the laser's center frequency. Fortunately, using a large mode-volume optical resonator, which suppresses the resonator's fast thermal fluctuations, together with the stimulated Brillouin scattering (SBS) optical nonlinearity presents a powerful combination that enables the ability to lase with an ultra-narrow linewidth of 20 Hz. The laser's long-term temperature drift is compensated by using the narrow Brillouin line to sense minute changes in the resonator's temperature (e.g., changes of 85 nK). The precision of this temperature measurement enables the stabilization of resonators against environmental perturbations.

The invention relates to a two-groove wide-ridge type semiconductor light amplifier, which comprises a substrate and an epitaxial layer growing on the substrate, wherein the upper part of the epitaxial layer comprises an n type waveguide layer, an active area quantum well layer, a p type covering layer and an ohmic contact layer; the active area quantum well layer is arranged at the upper part of the n type waveguide layer; the p type covering layer and the ohmic contact layer are arranged at the upper part of the active area quantum well layer; the partial region of the ohmic contact layer is vertically and downwards etched into the n type waveguide layer to form a two-groove limitation ridge type structure; two grooves are two mutually parallel grooves; the width of the ridge type structure is identical to the thickness of a ridge type waveguide. A waveguide coupling mode is adopted; a coplanar waveguide is used as a filter; the single-mode output in the large-mode volume is realized; the output power is increased; meanwhile, the coupling efficiency is also improved.

The invention relates to an optical chaos generating device based on a silicon photon microcavity. The optical chaos generating device comprises a tunable laser, an erbium-doped fiber amplifier (EDFA), a fiber polarization controller (FPC), an optical isolator (OI), a polarizing plate, a silicon photon microcavity and a photodetector (PD). The optical chaos generating device based on a silicon photon microcavity generates optical chaos by using the silicon photon microcavity, enables the optical chaos to be fully integrated with CMOS, has low manufacturing cost, is suitable for large-scale mass production, has a smaller model volume, a higher quality factor, high local energy density, good light control performance, is conducive to direct operation of light processing, achieves low-threshold operation, is fully integrated and good in actual stability.

The present invention relates to an ultrasound imaging system (10) comprising an ultrasound probe (20) having a transducer array (21) configured to provide an ultrasound receive signal. The system further comprises a B-mode volume processing unit (30) configured to generate a B-mode volume (31) based on the ultrasound receive signal, and a B-mode image processing unit (40) configured to provide a current B-mode image (41) based on the B-mode volume (31). The system further comprises a memory (50) configured to store a previously acquired 3D-vessel map (51). Also, the system comprises a registration unit (60) configured to register the previously acquired 3D-vessel map (51) to the B-mode volume (31) and to select a portion (61) of the 3D-vessel map corresponding to the current B-mode image (41). Further, the system comprises a display configured to display an ultrasound image (71) based on the current B-mode image (41) and the selected portion (61) of the 3D-vessel map (51). The present invention further relates to a method for providing such ultrasound image with vessel information and a corresponding computer program.

The invention discloses a semiconductor optical amplifier, and especially relates to a GaAs-based semiconductor optical amplifier having a parabola-shaped curved-surface waveguide structure. Material of the semiconductor optical amplifier is a GaAs-based material system. An N-type AlxGa1-xAs buffer layer, an N-type AlGaAsSb lower limit layer, an N-type N-AlxGa1-xAs lower waveguide layer, an InxGa1-xAs quantum well active region, a P-type AlxGa1-xAs upper waveguide layer and a P-type AlGaAsSb upper limit layer are epitaxially prepared on an N-type GaAs substrate in sequence. The upper waveguide layer of the semiconductor optical amplifier is in the parabola-shaped curved-surface structure; such structure can enable a parabola-shaped curved-surface tip to have higher photon density, thereby improving mode volume of the semiconductor optical amplifier and enabling the semiconductor optical amplifier to have higher gain; and meanwhile, the parabola-shaped curved-surface waveguide structure facilitates compressing divergence angle of the semiconductor optical amplifier, thereby realizing high-power output and improving fiber coupling efficiency. The parabola-shaped curved-surface structure of the upper waveguide layer of the semiconductor optical amplifier is prepared through electron beam lithography or ultra-violet lithography, and then, through a dry method and wet method combined etching process.

A chip-shaped laser medium (12) is side pumped to improve mode matching between the pumping energy (50) and lasing mode volume (36). The chip thickness (44) and laser medium doping level can be designed and controlled to ensure adequate pumping coupling efficiency. The chip shape can also be employed to provide greater chip surface areas (22) for cooling the laser medium (12). The laser pumping package (70), gain module (10₁), and chip-shaped design can be scalable to offer higher pumping power and high output power. Different orientations of the gain modules (10₁) with respect to each other can be used to provide better lasing mode quality.

The invention discloses a surface plasmon coaxial optical wave guide structure which relates to an optical wave guide. The surface plasmon coaxial optical wave guide structure is good for the light signal transmission. A cylindrical core layer and a tubular shell layer are arranged; the cylindrical core layer is a metal core layer; and the shell layer is a wide band-gap media shell layer. The surface plasmon coaxial optical wave guide structure taking metal as the core layer enlarges the transmitted light signal in the wave guide, and provides a resonant cavity with small mode volume, thereby improving fineness and facilitating transmission efficiency of the objective light signal.

The invention discloses a method for adopting a photonic crystal structure to realize the whispering gallery mode of a ring cavity. In the method, 12 photonic crystal air holes are removed from a complete triangular lattice photonic crystal in the semiconductor material; 6 photonic crystal air holes are added at the annular corners; and then the ring cavity of the photonic crystal can be formed. The whispering gallery mode of the ring cavity produced in the method has good quality factors, and the mode is only a plurality of microns in size, thereby solving the problem that the whispering gallery mode is difficult to be integrated to a small scale size.

The invention discloses an on-chip integrated cascade amplification semiconductor laser. The on-chip integrated cascade amplification semiconductor laser comprises a ridge type area, an on-chip DBR grating structure, a tapered type area and an epitaxial waveguide; the DBR grating structure is arranged on the ridge type area, the ridge type area is a ridge type waveguide structure, the tapered typearea is a gain waveguide structure; the epitaxial waveguide has a first-order ladder thickness; the ridge type area is arranged at a thin side of the epitaxial waveguide, the tapered type area is arranged at a thick side of the epitaxial waveguide, and the ridge type area and the tapered type area are cascaded. The laser of the design can more sufficiently utilize the tapered type area gain in comparison with a laser amplification way of traditionally utilizing the tapered gain structure; the base model feature is maintained when the mode volume is extended based on the iso-luminous flux principle, the optical quality of the near diffraction limit laser is guaranteed, and the brightness is greatly improved.

The invention provides a preparation method for a three-dimensional crystal optics echo wall micro-cavity. The preparation method comprises the steps: carrying out femtosecond laser selective ablation on crystals soaked in liquid and grinding the lateral wall of the micro-cavity by using a focused ion beam. The three-dimensional crystal optics echo wall micro-cavity prepared by adopting the method provided by the invention can be used for limiting light through continuous total internal reflection of the cavity and an outside face, and has the advantages of extremely high surface smoothness, small mode volume and high quality factor. The preparation method is applicable to various crystal materials, glass and the like.

A 1D nanobeam photonic crystal cavity is provided that includes a substrate, where the substrate includes a dielectric medium, and a series of cutout features in the substrate, where each cutout feature includes a first curved surface and a second curved surface, where the first curved surface and the second curved surface form a meniscus shape, where the series of cutout features include an array of sizes of the meniscus shape cutouts, where edges of the meniscus shape and the array of sizes are disposed to form a pair of opposing parabolic dips proximal to a central region of the series of cutout features.