33results about How to "Short pulse" patented technology

The invention discloses a negative dispersion pulse widening optical fiber amplifying device, which comprises a mode-locked laser, a negative dispersion unit, a primary amplifying unit, a secondary amplifying unit and an output unit, wherein the mode-locked laser generates seed light pulse; the negative dispersion unit is arranged at the emergent side of the seed light pulse of the mode-locked laser to widen the seed light pulse and enable the seed light pulse to have negative chirp; the primary amplifying unit receives the seed light pulse with the negative chirp, which is output by the negative dispersion unit, carries out primary amplification, and further carries out positive dispersion compensation on the negative chirp in the seed light pulse to shorten the seed light pulse; the secondary amplifying unit receives the seed light pulse output by the primary amplifying unit, carries out secondary amplification, and further carries out positive dispersion compensation on the negative chirp in the seed light pulse to shorten the seed light pulse; and the output unit is connected with the secondary amplifying unit and outputs the amplified seed light pulse. The invention makes the pulse of the output end of the optical fiber amplifier shortest via the negative dispersion widening, simplifies the system, reduces the loss, increases the pulse energy after the amplifier, and effectively reduces the cost.

The present invention relates to a method for identifying an entity comprising placing an internal tag within the entity and placing an external tag proximate the entity wherein the internal tag and external tag are coupled.

The present invention contemplates a simplified laser oscillator-amplifier system for deep UV generation. The simplified system employs same type of gain media in both the oscillator and the amplifier and utilizes a single pump pulse split to pump both the oscillator and the amplifier. A short cavity oscillator is operated near lasing threshold to produce a seed pulse with a narrow spectral bandwidth and long pulse duration. A short cavity amplifier is Q-switched to amplify the seed pulse to produce a single short pulse with good energy extraction efficiency. The amplifier is simply a short cavity, Q-switched laser. Short pulse is obtained with short cavity length and high gain of the amplifier. Consequently, the simplified laser oscillator-amplifier system can accommodate a long pump pulse to produce a nanosecond pulse suitable for deep UV laser generation.

A thermal inkjet printhead with a heater element disposed in each of the bubble forming chambers wherein, the heater element has a protective surface coating that is less than 0.1 μm thick while still being capable of ejecting more than 1 billion drops without failure. Removing most or all of the protective coatings from the heater reduces or eliminates the thermal insulation between the heater and the ink. Nucleating a bubble in the ink chamber requires a much shorter pulse of less energy thereby improving printhead efficiency.

The invention discloses an independent tuning microwave electron gun with external cathode which is composed of an external negative pole, namely, dipolar gun, a microwave cavity, a tuning mechanism, a first cavity input waveguide, a second cavity input waveguide and a cooling water pipe; the external negative pole and the microwave cavity are connected by Kovar flange argon-arc welding, the tuning mechanism and the microwave cavity are connected by braze welding in a hydrogen furnace, the first cavity input waveguide and the second cavity input waveguide are connected with the microwave cavity by braze welding, but the first cavity input waveguide and the second cavity input waveguide are connected at different longitudinal positions of the microwave cavity with the angles being mutually perpendicular, and then connected with a waveguide transmission line fed with microwave power respectively. The invention is designed to solve manufacture technique, so that the electron gun has simple structure and electron beam is excellent in performance, thus providing a novel electron beam source device for compact type free electron laser and electron linear accelerator.

The invention discloses a 2.79 mu m Q-switched erbium laser dental instrument. The 2.79 mu m Q-switched erbium laser dental instrument comprises a laser power supply, a laser component, a laser water cooling system, a light guide output system, a gas and water spraying system and a central control system; the laser power supply is used for providing energy to the laser component; the laser component consists of a total-reflection chamber piece, a polarizer, a Q-switched crystal, a xenon lamp, a laser rod, a light condensing chamber, a wave plate and an output chamber piece; the laser water cooling system is used for cooling the laser rod and the xenon lamp in the laser component; the light guide output system is used for conducting laser, and is convenient to operate and use; the gas and water spraying system is used for spraying a mixture of gas and water to a laser acted tooth tissue, and has the effects of reducing the temperature of the tissue and participating laser treatment; the central control system is used for controlling the parameters of the laser power supply, the laser water cooling system and the gas and water spraying system to ensure the coordination work among the subsystems. The 2.79 mu m Q-switched erbium laser dental instrument has pulse Q-switched laser which has short pulse width and high peak power and acts the tooth tissue to improve ablation precision; meanwhile, the thermal damage to peripheral tissues also can be effectively reduced; the pain of a patient can be reduced effectively.

The invention discloses a medical 2.79-micrometer electro-optical Q-switched Cr, Er: YSGG (Erbium, Chromium: Yttrium-Scandium-Gallium-Garnet) laser device which comprises a total reflection cavity sheet, a Q-switched crystal, a polarizer, a xenon lamp, a laser rod, a condensation cavity, a wave sheet, an output cavity sheet, a laser power supply and a laser water cooling system, wherein the laser rod and the xenon lamp are mounted in parallel in the condensation cavity, and connected with the water cooling system; the water cooling system cools the condensation cavity, and the laser rod and the xenon lamp in the condensation cavity; the laser power supply provides electric energy for the xenon lamp, and has a function of coordination, such as controlling the xenon lamp, an electro-optical Q switch, and the water cooling system; a Q-switched power supply in the power supply controls the opening time of the electro-optical Q switch, provides Q-switched high voltage, and is connected with two electrodes of the Q-switched crystal; the two electrodes are positioned on the two sides of the Q-switched crystal, and clung to the surface of a Y-Z plane of the Q-switched crystal, and are parallel to a laser oscillation path; the electro-optical Q switch consists of the polarizer and the electro-optical Q-switched crystal; the Q-switched crystal is a lanthanum gallium silicate (LGS) crystal; the laser rod is a Cr, Er: YSGG laser crystal; and the wave sheet is a 1/4 wave sheet. The laser device has the characteristics of stable output power, and uniform light spot intensity distribution.

The invention provides a pre-chirp management femtosecond pulse laser coherent combination amplification device. The device comprises a femtosecond laser front-end module, a pre-chirp management module, a pulse beam splitter module, an optical fiber amplifier module, a pulse beam combiner module, a pulse compression module and a time delay adjustment module. The pre-chirp technology is adopted to increase the spectrum broadening amount, the coherent combination technology is adopted to increase the output average power, and two paths of coherent combination can output sub-50 femtosecond ultrashort pulses with the average power of five hundred watts; meanwhile, the expansibility is high, a plurality of rod-shaped photonic crystal gain optical fibers can be added in parallel on the basis of an existing system to further improve the output average power, and a pulse separation/synthesis unit in time can be added to improve the output pulse energy of the system.

The present invention provides a positive electron beam transmission system. The laser in the system is emitted from a laser source, enters a vacuum target chamber and is reflected by a plane mirror onto the reflection focusing mirror of an off-axis paraboloid; and the laser is focused at the position about 2mm far away from the top of a gas target assembly, a tantalum target is located behind the gas target assembly, and a sighting device is located behind the tantalum target. The beam transmission system comprises a vacuum pipeline, a solenoid coil, a dipolar magnet, a beam dustbin, the sighting device and another solenoid coil. The positive electrons and electrons enter the vacuum pipeline at the outside of the vacuum target chamber together and are focused by the solenoid coil, then negative electrons pass through the dipolar magnet and enter the beam dustbin, and the positive electrons pass through the sighting device and are focused by the solenoid coil behind the sighting device.

A continuous or a long-pulsed microwave oscillated from a microwave oscillator 1 is propagated in a waveguided tube 2 in which a given gas is charged. Subsequently, by irradiating a laser having a given intensity from a laser source 4 to the points, A and B in the tube 2, the given gas is partially made plasma. Just then, the microwave can not travel beyond the plasma-part of the given gas and reflects thereat. Accordingly, the microwave is divided at the plasma-part and thereby, a short-pulsed microwave can be obtained.

An adaptive bitrate streaming method streams audio video (AV) to a client using a multi content delivery network (CDN) approach. Each CDN stores versions of content that can be requested in a succession of consecutive files using HTTP requests. The method is based on use of an intermediate module between an AV player of the client and each CDN. For each file of a version requested by the AV player, the intermediate module requests a manifest file to each CDN and estimates a bitrate of each CDN using reception performances of the manifest files. Each file is requested by the intermediate module in a succession of segment groups according to a pattern including a predetermined number of segments. Each group includes one set of segments for each CDN, each set including segments to be requested to the CDN to which they correspond proportional to the bitrate of this CDN.

Disclosed is a device for, in combination with a stop having an aperture, generating charged particle beam pulses, an apparatus for inspecting a surface of a sample, and a method for inspecting a surface of a sample. The device includes a deflection unit which is arranged for positioning in or along a trajectory of a charged particle beam. The deflection unit is arranged for generating an electric field for deflecting said charged particle beam over the stop and across the aperture. The device also includes an electrical driving circuit for providing a periodic signal. The electrical driving circuit is connected to the manipulation unit via a photoconductive switch, wherein the photoconductive switch is arranged for: substantially insulating the deflection unit from the electrical driving circuit, and for conductively connecting the deflection unit to the electrical driving circuit only when said photoconductive switch is illuminated by a light beam.

The invention belongs to the technical field of femtosecond lasers, and discloses a large-energy-cavity-dumped Yb femtosecond laser which comprises a pumping source, an optical coupling system, a planar dichroic mirror, a Yb laser crystal, a first concave mirror, a second concave mirror, an output mirror, a first GTI mirror, a second GTI mirror, a third GTI mirror, a third concave mirror, a nonlinear medium, a fourth concave mirror, a TFP, an electro-optical modulator and a planar mirror. The cavity-dumped laser is based on a high-power Kerr lens mode-locked oscillator, starts mode locking without the help of an SESAM device prone to damage, and guarantees that mode-locked pulses in a cavity have the short pulse width and the high single pulse energy; and after the large-energy short-pulse-width pulse in the cavity is stably oscillated, the electro-optical modulator is used for changing a polarization state of laser, and the pulse laser larger than 0.5 mu J and smaller than 100 fs in pulse width can be effectively guided out and achieved in combination with the TFP.

The invention discloses a spectrometer calibration spectral line generator and a generation method thereof. A high-repetition-frequency femtosecond fiber laser is adopted, the output power is high, the pulse is short, a super-continuum spectrum is directly generated in a photonic crystal fiber, and the system is simplified; another set of device required for generating an octave spectrum is omitted, so that the system is further simplified; the side mode rejection ratio after filtering of an ultra-stable cavity is high, the noise is low, and distinguishing in a spectrograph is facilitated; asthe light of different spectral bands is subjected to ultra-stable cavity filtering and frequency interval multiplication in different spectrum elimination intervals at the same time, calibration spectra of different bands and different frequency intervals can be obtained at the same time, the spectra can be clearly distinguished in the whole spectrograph detection interval, and the enough numberof calibration spectral lines are provided; and a spectrum flattening reflector is adopted, a common device of a grating and a spatial modulator is omitted, the reflector eliminates too high spectrumcomponents, space and cost are saved, and stability and operability of the system are also improved.

The invention, which relates to the technical field of laser resistor trimming, discloses a method for precise resistor trimming on a flexible substrate by using ultrafast laser. Precise resistor trimming of a flexible circuit board is carried out by using ultrafast laser creatively; and the ultrafast laser material removing process is a cold treatment process, and only the material zone under theultrafast laser effect is removed but the surrounding material is not affected obviously. Meanwhile, the ultrafast laser has the short pulse. The resistor trimming by using the ultrafast laser has the following advantages: firstly, the resistor trimming precision is improved; secondly, the resistive material/structure is protected from being damaged; and thirdly, the thermal damage of the substrate is avoided. Moreover, since the existing flexible devices are made of flexible non-metallic materials that include glass or plastic materials and the like and have the thicknesses of more than tenor even tens of micrometers, the resistor trimming needs cold-processing ultrafast laser due to the high temperature sensitivity of the devices. Therefore, the method has broad application prospects.

The invention relates to a medium laser accelerator and a vertical cavity surface laser. An XYZ space rectangular coordinate system is defined. The medium laser accelerator comprises a vertical cavity surface laser, the vertical cavity surface laser comprising an active layer and an acceleration area arranged in front of the Z-axis direction of the active layer, the main extension plane of the active layer being parallel to the plane defined by the X axis and the Y axis, and the acceleration region being provided with an acceleration channel parallel to the X-axis direction; a reflecting mirror, arranged on a light path of the laser emitted by the vertical cavity surface laser and used for reflecting the laser emitted by the vertical cavity surface laser at a specific angle; and a saturable absorption mirror, having corresponding absorptivity for the laser with different light intensities reflected by the reflecting mirror, and can compress the pulse width of the laser and reflect the compressed laser back to the vertical cavity surface laser through the reflecting mirror. A higher accelerating electric field can be obtained in an accelerating area, and the accelerating gradient of the medium laser accelerator is improved.