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634 results about "Cw laser" patented technology

Single-wall carbon nanotubes from high pressure CO

The present invention discloses the process of supplying high pressure (e.g., 30 atmospheres) CO that has been preheated (e.g., to about 1000° C.) and a catalyst precursor gas (e.g., Fe(CO)5) in CO that is kept below the catalyst precursor decomposition temperature to a mixing zone. In this mixing zone, the catalyst precursor is rapidly heated to a temperature that results in (1) precursor decomposition, (2) formation of active catalyst metal atom clusters of the appropriate size, and (3) favorable growth of SWNTs on the catalyst clusters. Preferably a catalyst cluster nucleation agency is employed to enable rapid reaction of the catalyst precursor gas to form many small, active catalyst particles instead of a few large, inactive ones. Such nucleation agencies can include auxiliary metal precursors that cluster more rapidly than the primary catalyst, or through provision of additional energy inputs (e.g., from a pulsed or CW laser) directed precisely at the region where cluster formation is desired. Under these conditions SWNTs nucleate and grow according to the Boudouard reaction. The SWNTs thus formed may be recovered directly or passed through a growth and annealing zone maintained at an elevated temperature (e.g., 1000° C.) in which tubes may continue to grow and coalesce into ropes.
Owner:RICE UNIV

Mode-locked multi-mode fiber laser pulse source

A laser utilizes a cavity design which allows the stable generation of high peak power pulses from mode-locked multi-mode fiber lasers, greatly extending the peak power limits of conventional mode-locked single-mode fiber lasers. Mode-locking may be induced by insertion of a saturable absorber into the cavity and by inserting one or more mode-filters to ensure the oscillation of the fundamental mode in the multi-mode fiber. The probability of damage of the absorber may be minimized by the insertion of an additional semiconductor optical power limiter into the cavity. To amplify and compress optical pulses in a multi-mode (MM) optical fiber, a single-mode is launched into the MM fiber by matching the modal profile of the fundamental mode of the MM fiber with a diffraction-limited optical mode at the launch end, The fundamental mode is preserved in the MM fiber by minimizing mode-coupling by using relatively short lengths of step-index MM fibers with a few hundred modes and by minimizing fiber perturbations. Doping is confined to the center of the fiber core to preferentially amplify the fundamental mode, to reduce amplified spontaneous emission and to allow gain-guiding of the fundamental mode. Gain-guiding allows for the design of systems with length-dependent and power-dependent diameters of the fundamental mode. To allow pumping with high-power laser diodes, a double-clad amplifier structure is employed. For applications in nonlinear pulse-compression, self phase modulation and dispersion in the optical fibers can be exploited. High-power optical pulses may be linearly compressed using bulk optics dispersive delay lines or by chirped fiber Bragg gratings written directly into the SM or MM optical fiber. High-power cw lasers operating in a single near-diffraction-limited mode may be constructed from MM fibers by incorporating effective mode-filters into the laser cavity. Regenerative fiber amplifiers may be constructed from MM fibers by careful control of the recirculating mode. Higher-power Q-switched fiber lasers may be constructed by exploiting the large energy stored in MM fiber amplifiers.
Owner:FERMANN MARTIN E +1

Fiber lasers

Fiber lasers for producing Band I wavelengths include a laser cavity having an optical fiber with specific parameters in length and thickness and doping concentration, and having high reflectivities. Examples show the feasibility of producing such fiber lasers. Fiber lasers for producing Band IV wavelengths include a depolarized laser oscillator, at least one amplifier and a polarizer. Depolarized laser oscillator is an inherently depolarized CW laser, or a depolarized laser diode, which is depolarized by a depolarizer. Additional fiber lasers in accordance with embodiments of the present invention include a double clad active optical fiber having a pump power entry point for sending pump energy through the active optical fiber in a first direction, and a loop portion at a second end of the fiber for sending pump energy through the active optical fiber in a second direction which is opposite to the first direction. A system for coupling light into a fiber in accordance with embodiments of the present invention include a first fiber, a second double clad fiber, and a bulk optic component positioned between the first and second fibers. A mode stripper included within the second fiber allows for removal of high power light which is propagated through the outer clad rather than launched into the core of the second fiber.
Owner:ELBIT SYST ELECTRO OPTICS ELOP

Method and device for simultaneously measuring droplet position, particle sizes and complex refractive index

The invention relates to technology for simultaneously measuring multi-phase flow particles online through multi-parameter, and aims to provide a method and a device for simultaneously measuring droplet positions, particle sizes and a complex refractive index. The method comprises the following steps of: (1) dividing a highly coherent continuous laser beam into two beams after spatial filtering and collimating beam expansion, wherein one beam radiates particles in a detected flow field region, and the other beam is used as a reference beam; (2) mixing scattered light of a lateral 30-degree to 90-degree region of particles in the detected flow field region and the attenuated reference beam to perform interference so as to form a hologram, storing the hologram in a computer after being recorded by a digital camera through an imaging device; (3) acquiring a series of reconstructed images of the detected particles along the depth direction by utilizing digital reconstruction technology; and (4) identifying the reflective spot and the refractive spot of the particles from the reconstructed images by utilizing digital image processing technology so as to acquire space coordinates and scattered light intensity ratios. Compared with rainbow measurement technology, the measurement method has the advantages that: a light path system of the measurement device is relatively simple and is easy to implement.
Owner:ZHEJIANG UNIV

Device and method for laser shot blasting reinforcement of hard and brittle material

InactiveCN101962710AImprove surface integritySuppress micro cracksMetallic materialsShielding gas
The invention discloses a device and a method for laser shot blasting reinforcement of a hard and brittle material, and relates to the field of mechanical manufacture of hard and brittle material processing and laser application. The device comprises a laser aid heating system, a laser shot blasting reinforcement system, a workpiece clamp system, a computer numerical control system, a measurement feedback system and a protective gas circulating system. The method comprises a laser aid heating stage and a laser shot blasting reinforcement stage, namely performing aid heating treatment on the area to be reinforced by adopting high-power continuous laser, wherein for most metal materials, the plastic performance is improved along with the rise of temperature; and after the temperature of the heating area reaches a predetermined heating temperature, implementing laser shot blasting reinforcement treatment by adopting high-power pulse laser. The device and the method can implement the laser shot blasting reinforcement on the hard and brittle material so as to broaden the application range of the laser shot blasting reinforcement technology, and meanwhile compound the advantages of continuous laser and pulse laser so as to broaden the application field and the application prospect of laser manufacture.
Owner:JIANGSU UNIV

Laser irradiation apparatus, laser irradiation method, and method for manufacturing semiconductor device

An aggregation of crystals extending long in the scanning direction (a long crystal grain region) is formed when a continuous wave laser oscillator (a CW laser oscillator) is employed for annealing the semiconductor film in the manufacturing process of a semiconductor device. The long crystal grain region has a characteristic similar to that of single crystal in the scanning direction, but there is restriction for high integration because of the small output of the CW laser oscillator. pa In order to solve the problem, a pulsed laser beam 1 having a wavelength absorbed sufficiently in the semiconductor film is used in combination with a laser beam 2 having a high output and having a wavelength absorbed sufficiently in the melted semiconductor film. After irradiating the laser beam 1 to melt the semiconductor widely, the laser beam 2 is irradiated to the melted region. And then the laser beam 2 and the semiconductor film are moved relatively while keeping the melting state so as to form the long crystal grain region. The laser beam 2 keeps to be irradiated to the semiconductor film until the laser beam 1 is irradiated, and the output of the laser beam 2 is attenuated when the laser beam 1 is irradiated so as not to give the energy more than is needed so that the very uniform laser annealing becomes possible. Thus the long crystal grain region having a width 10 times as broad as the conventional one can be formed.
Owner:SEMICON ENERGY LAB CO LTD
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