38 results about "Pulse energy density" patented technology

A method of measuring at least one property including a magnetic property of target material is provided. The method includes the step of generating a pump pulse train having one or more pump pulses at a repetition rate along a first propagation path, each pump pulse having a pulse energy density, a laser wavelength within a range of laser wavelengths, and a pulse duration The method further includes the step of irradiating the target material with at least a portion of the one or more pump pulses focused into at least one spot having a spot shape and size so as to cause transient perturbation in the target material. The method still further includes the step of generating at least one probe pulse train having one or more probe pulses at a repetition rate along a second propagation path, each probe pulse having a pulse energy density, a laser wavelength within a range of laser wavelengths, and a pulse duration. The method further includes the step of irradiating the target material with at least a portion of the one or more probe pulses focused into at least one spot having a spot shape and size to obtain one or more reflected probe pulses which are modulated based on the transient perturbation. The method still further includes the step of electronically controlling a time interval between a time at which the target material is irradiated by each of the focused pump pulses and a time at which the target material is irradiated by each of its corresponding focused probe pulses. The method further includes the step of detecting each modulated probe pulse to obtain one or more corresponding signals. The method still further includes the step of processing the one or more signals to obtain one or more measurement signals which represents the at least one property including the magnetic property of the target material.

The invention discloses a laser processing system and method. The laser processing system comprises a laser machine, an optical system, a sensor, a processor and a controller, wherein the laser machine is used for providing laser needed for processing, the optical system is arranged above a workpiece table and is used for adjusting the size of a laser spot, and projecting the adjusted laser spot onto the workpiece table, the sensor is arranged above the workpiece table and is used for collecting parameter information of workpiece material, the processor is connected with the sensor and is used for receiving and processing the parameter information acquired by the sensor to obtain the size of the laser spot needed by the workpiece material, and the controller is connected with the processor and is used for receiving the information of the processor to control the optical system. According to the laser processing system, the parameter information of the workpiece material is collected in real time through the sensor, the required size of the laser spot is calculated through the processor, the laser pulse energy density is adjusted in real time by adopting the controller to control the optical system to change the size of the laser spot, so that the real-time performance is good, and the cutting efficiency is high; and in the cutting process, the laser machine outputs lasers at the rated laser power all the time, and the utilization rate of laser energy is improved.

A source of hydrogen is a glass or glass-ceramic shell and a gas comprising at least 80% by volume of hydrogen. The glass shell has an initial permeability to hydrogen gas of less than about 50% decrease in pressure in 30 days and a final permeability to hydrogen of about 50% decrease in pressure in a few minutes or less, upon exposure of the glass to a continuous or pulsed fluence of at least 0.1 W/cm² of electromagnetic radiation to modulate the microstructure of the glass and to increase the hydrogen gas permeability of the glass network. A method of providing hydrogen gas in the shell and exposing the shell to electromagnetic radiation of a wavelength and fluence that increases permeability of the shell to hydrogen gas so that encapsulated hydrogen gas permeates through the shell.

A method for laser marking a metal surface (5) with a desired colour, which method comprises forming at least one first pattern (41) on the metal surface (5) with a first laser beam (42) having a first pulse fluence (43), forming at least one second pattern (51) on the metal surface with a second laser beam (52) having a second pulse fluence (53), characterized by causing the second pattern (51) to overlay the first pattern (41), arranging the first pulse fluence (43) to be at least five times greater than the second pulse fluence (53), the colour being given by the first and second pulse fluences (43, 53) and spot spacings (48) in the first and second patterns (41, 51), and selecting the first and second pulse fluences (43, 53) and the spot spacings (48) to form the desired colour.

The invention relates to a non-crystal fine processing method which uses femtosecond laser to process non-crystal alloy, wherein said method uses femtosecond laser to make hole, etch, and cut the non-crystal alloy, while the impulse energy density of femtosecond laser is 50-100H/cm2 and the impulse width is 45-100fs in holing; the impulse energy density is 3-15J/cm2, the impulse width is 45-100fs, and the scanning speed is 100-200 mum/s in etching line; the impulse energy density is 75-110J/cm2, the impulse width is 45-100fs, and the scanning speed is 100-200 mum/s in cutting. The invention can realize sub-micron processing accuracy, without crystallization in etching area.

A method of forming a via hole reaching a bonding pad in a wafer having a plurality of devices formed on the front surface of a substrate and bonding pads formed on each of the devices by applying a pulse laser beam to the rear surface of the substrate, the method comprising the steps of:

• • forming a non-through hole having a predetermined depth in the front surface of the substrate by applying a pulse laser beam having a spot diameter of 0.75 to 0.9 D when the diameter of the via hole to be formed is represented by D and an energy density per pulse of 40 to 60 J/cm² to the rear surface of the substrate; and
  • forming a via hole reaching a bonding pad in the substrate by applying a pulse laser beam having an energy density per pulse of 25 to 35 J/cm² to the hole formed in the substrate.

A method for laser marking a metal surface (5) with a desired colour, which comprises forming at least one first pattern (41) on a metal surface (5) with a first laser beam (42) having a first pulse fluence (43), forming at least one second pattern (51) on the metal surface with a second laser beam (52) having a second pulse fluence (53), characterized by causing the second pattern (51) to overlay the first pattern (41), arranging the first pulse fluence (43) to be at least five times greater than the second pulse fluence (53), the colour being given by the first and second pulse fluences (43, 53) and spot spacings (48) in the first and second patterns (41, 51), and selecting the first and second pulse fluences (43, 53) and the spot spacings (48) to form the desired colour.

The invention discloses a multiple wave band narrowband high power microwave-based damage effect test method for an electroacoustic alarm controller. The electroacoustic alarm controller is placed in a test zone, and the method comprises the following steps: in step a1, L wave band high power microwave radiation is set in a system, and the electroacoustic alarm controller faces right to radiation wave waves; in step a2, the electroacoustic alarm controller faces sideways to the radiation wave waves; in step a3, the electroacoustic alarm controller faces in a direction opposite to the radiation waves; in step a4, a polarization mode is changed to a vertical polarization mode; in step a5, a wire cable is hidden in wave absorbing material; in step a6, minimum pulse energy density in steps from step a1 to step a5 is chosen as an interference threshold value for a sample; in step a7, the sample is changed, the steps from step a1 to step a6 are repeated; in step a8, a threshold value range of damage caused on the electroacoustic alarm controller by a wave band high power microwave; in step a9, the microwave radiation system is orderly adjusted to be an S wave band microwave radiation system, a C wave band microwave radiation system and an X wave band microwave radiation system; the test steps from step a1 to step a8 are repeated. The damage effect test method is advantaged by well-organized structure, strong pertinency, easy-to-implement property and the like.

The invention discloses a method for inducing a periodic structure on the surface of optical glass by picosecond laser. The method specifically comprises the following steps: a picosecond laser beam is focused on the surface of the optical glass through a beam expanding and focusing device, after 1-20 pulses act, LIPSS is formed on the surface, and the energy density range of the single laser is 0.4-0.9 times of the ablation threshold. The optical characteristics of the glass can be changed, the surface reflectivity is reduced and the transmittance is improved.

The once double holographic micro grating writing process includes the following steps: adopting supershort pulse laser with pulse width smaller than 1 ps; splitting in a splitter into two beams focused separately by two convexes and crossed at or near the focus to realize temporal and spatial coherent; adopting transparent solid medium; controlling the energy of single pulse output by the laser to make each of the split pulse possess energy density smaller than that energy density threshold to ablate the transparent medium and the energy density reached in constructive interference just greater than the threshold; converging the two coherent supershort laser beams onto the surface of the transparent medium to produce two periodical microstructures and to form double holographic micro grating simultaneously.

The present invention enables uniform crystallization of a semiconductor film by means of laser annealing. The present invention comprises a pulse laser oscillating device for outputting a pulse laser beam, and an optical transmission means for transmitting the pulse laser beam outputted from the pulse laser oscillating device to irradiate onto the semiconductor film. Since the pulse laser beam, which has an effective power density on the irradiated surface of the semiconductor film calculated by the formula of effective power density (J / (sec.cm3)) = pulse energy density (J/cm2) / pulse width (sec) absorption coefficient of semiconductor film (cm-1), is irradiated onto the semiconductor film so as to be in a range of 3 1012 to 1.5 1012, the semiconductor film can be crystallized without inducing abnormal grain growth due to complete melting, and uniform crystals with little variation are obtained.

The invention relates to the field of perovskite nanosheet lasers. The invention discloses a surface tetraphenyl dibenzodiindenopyrene (DBP) protective layer for improving the stability of a perovskite nanosheet laser and a preparation method thereof. The good hydrophobic property of the DBP material can effectively prevent water vapor from damaging a perovskite layer, so that the air stability ofthe device is improved. Meanwhile, the electron temperature and the lattice temperature of the active medium of the perovskite layer in the perovskite laser are increased under the condition of highlaser pulse energy density, and the high temperature resistance of the DBP film is beneficial to reducing the thermal decomposition of the perovskite layer, so that the thermal stability of the perovskite laser is improved. The invention relates to the surface protection layer for improving the stability of the perovskite nanosheet laser and the preparation method thereof.

In the present invention, prepared is a silicon wafer having implanted in a surface layer part of one surface thereof an element that forms composite defects which function as donors when activated. Apulsed laser beam having a wavelength in the range of 690 to 950nm inclusive is caused to enter a laser irradiation surface of the silicon wafer, which is the surface where the element has been implanted, in order to activate the element. During the activation of the element, the pulse width of the pulsed laser beam and the pulse energy density are set such that the pulsed laser beam enters the silicon wafer under the conditions that the element in at least some regions from the surface to a depth of 40[mu]m is activated without melting the laser irradiation surface.

The invention relates to a method for calibrating the incident energy density of the front surface of a wafer, which comprises the following steps of: providing an undoped wafer, annealing by adopting laser with different energy densities, controlling the uncalibrated energy density by a feedback loop, and providing the measurement of the incident energy density in any unit; in the annealing process, surface roughness testing is conducted on a wafer through an AFM, and a threshold value change point at the beginning of surface melting and the corresponding actual incident energy density are obtained; and according to the incident energy density of any unit and the actual incident energy density corresponding to the threshold value change point, incident energy density calibration is carried out. According to the method, the incident laser pulse energy density is calibrated by using the sudden threshold change of the surface roughness measured by the AFM at the beginning of wafer surface melting; performing incident ED period monitoring on sub-melt boron doping activation of the silicon substrate at the temperature of 1300 DEG C; tool and process matching is performed using epitaxial regrowth of an amorphous doped silicon phosphorus layer at 1200 DEG C or below, and the matching is in the range of 1% of the energy density.