50 results about "Laser pulse shaping" patented technology

The present invention determines the dimensions and volume of an object by using a novel 3-D camera that measures the distance to every reflective point in its field of view with a single pulse of light. The distance is computed by the time of flight of the pulse to each camera pixel. The accuracy of the measurement is augmented by capture of the laser pulse shape in each camera pixel. The camera can be used on an assembly line to develop quality control data for manufactured objects or on a moving or stationary system that weighs as well as dimensions the objects. The device can also ascertain the minimum size of a box required to enclose an object.

Laser pulse shaping techniques produce tailored laser pulse spectral output. The laser pulses can be programmed to have desired pulse widths and pulse shapes (such as sub-nanosecond to 10 ns-20 ns pulse widths with 1 ns to several nanoseconds leading edge rise times). Preferred embodiments are implemented with one or more electro-optical modulators receiving drive signals that selectively change the amount of incident pulsed laser emission to form a tailored pulse output. Triggering the drive signal from the pulsed laser emission suppresses jitter associated with other stages of the link processing system and substantially removes jitter associated with pulsed laser emission build-up time.

Tailored laser pulse shapes are used for processing workpieces. Laser dicing of semiconductor device wafers on die-attach film (DAF), for example, may use different tailored laser pulse shapes for scribing device layers down to a semiconductor substrate, dicing the semiconductor substrate, cutting the underlying DAF, and / or post processing of the upper die edges to increase die break strength. Different mono-shape laser pulse trains may be used for respective recipe steps or passes of a laser beam over a scribe line. In another embodiment, scribing a semiconductor device wafer includes only a single pass of a laser beam along a scribe line using a mixed-shape laser pulse train that includes at least two laser pulses that are different than one another. In addition, or in other embodiments, one or more tailored pulse shapes may be selected and provided to the workpiece on-the-fly. The selection may be based on sensor feedback.

A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and a spectrometer. Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal. In yet another aspect of the present invention, a multiphoton intrapulse interference phase scan system and method characterize the spectral phase of femtosecond laser pulses. Fiber optic communication systems, photodynamic therapy and pulse characterization tests use the laser system with additional aspects of the present invention.

A laser system for medical treatment is disclosed which comprises a pump, wherein the laser system is adapted to be operated in pulsed operation so that at least one laser pulse of a temporally limited pulse duration (Tp) is generated. The generated laser pulse irradiates some part of the human or animal body so that a two-dimensional laser spot S is located on the top layer of the irradiated part of the human or animal body. The pump power of the pump of the laser system is modulated in such a way that the cumulative energy ES(Tp / 2) which is delivered by said laser pulse to said laser spot S during the first half of the pulse duration is less than 45% of the energy ES(Tp) which is delivered by said laser pulse to said laser spot S during the entire pulse duration Tp.

The invention discloses a shaping method of a difference frequency terahertz pulse and a shaping system thereof. In the shaping method, a laser pulse shaping device is used for realizing the programmable shaping of a laser pulse; two arrays of laser pulses passing through the converting and shaping device are regulated to be mutually vertical in polarization directions and then are overlaid in a non-linear crystal and subjected to difference frequency to generate a terahertz wave; and through controlling the wave forms and the phases of the two arrays of the laser pulses with mutually vertical polarization directions, the wave form and the electric field polarization direction of the generated terahertz pulse can be controlled and the wave form and the polarization direction of generated terahertz radiation can be detected. The invention not only can control the wave form and the pulse interval of the terahertz pulse, but also can control the electric field polarization direction of the terahertz pulse. Compared with a scheme for shaping the terahertz pulse by using a photoconductive antenna or through an optical rectification process, the invention has obvious advantages.

The invention relates to an optical diagnostic system on the basis of laser spontaneous Raman scattered ray imaging, belonging to the technical field of laser spectrum testing. According to the invention, a laser pulse shaper is arranged between a laser and a gas sample tank; a cutoff device is arranged at one end of a laser emergence quartz window of the gas sample tank; a total reflective mirror is arranged between an outlet of a scattered ray output quartz window of the gas sample tank and a line light source collector at an angle of 45 degrees; an optical filter is arranged between the line light source collector and an inlet of a spectrometer; an outlet of the spectrometer is respectively connected with an ICCD (Intensified Charge Coupled Device) and an inlet of a measurement and control machine; the ICCD is also respectively connected with the laser and the measurement and control machine; and due to the adoption of the optical diagnostic system, the phenomena of gas fracturing,damage to optical elements and the quartz windows, ignition of inflammable gases and the like can be effectively avoided, the weak Raman scattering signal to noise ratio can be effectively improved, and a multichannel gas Raman spectrum experiment proves that the optical diagnostic system can be applied to synchronous quantitative measurement in a plurality of regions of the gas mixture concentration in an optical engine.

A laser pulse shape measuring system to measure the pulse shape of pulses generated by a pulsed laser. Each pulse includes a pulse width and a peak wavelength. The system includes: a beam splitter coupled to the laser to separate each of the pulses into a test pulse and a probe pulse; a pulse width compression means coupled to the beam splitter to compress the pulse width of each probe pulse; a controllable delay means to control a time offset between each test pulse and a corresponding probe pulse; a nonlinear optical medium arranged such that the test beam path and the probe beam path intersect within it to generate wavelength converted pulses corresponding to intersecting pairs of pulses; a detector coupled to the nonlinear optical medium to detect the pulse energies of the wavelength converted pulses; and a processor to determine the pulse shape of the laser pulses.

Our invention allows for control of particle formation at the nanoscale, providing a means to control nanoparticle and nanostructure formation using feedback on the fly from nanoparticle characteristic analysis and optimization / knowledge extraction control algorithms. A closed loop feedback controller causes the interaction of a shaped flaser pulse with a substrate. The substrate can be one or more solid, liquid or gas or any combination thereof. Nanoparticles are produced and their characteristics are measured. The measured characteristics are compared with the desired nanoparticle characteristics. If the measured and desired characteristics are not equivalent, the closed loop feedback controller modifies the shape of the laser pulse and the next cycle begins. With successive loop of the control process the difference between the desired and measured characteristics converges until they are equivalent. At the end of the process a relationship is developed between the desired nanoparticle characteristics and the laser pulse shape. A catalog of all pulse shapes generated and the resulting nanoparticle characteristics is generated each time the processor is cycled whether or not the nanoparticle characteristics are those desired.

The present invention determines the dimensions and volume of an object by using a novel 3-D camera that measures the distance to every reflective point in its field of view with a single pulse of light. The distance is computed by the time of flight of the pulse to each camera pixel. The accuracy of the measurement is augmented by capture of the laser pulse shape in each camera pixel. The camera can be used on an assembly line to develop quality control data for manufactured objects or on a moving or stationary system that weighs as well as dimensions the objects. The device can also ascertain the minimum size of a box required to enclose an object.

A measuring device for femtosecond laser pulse shapes structurally comprises a four-small pore plate, a medium delay piece, a reflector with partial area coated, a paraboloid reflector, a third-order nonlinear medium piece, a small-hole aperture, a focusing lens, a concave reflector and a high resolution spectrograph. And an output end of the high resolution spectrograph is connected with an input end of a computer. The measuring device for femtosecond laser pulse shapes has the advantages of simple and practical structure, convenience for adjusting, quickness in data collection and data processing and suitability for measuring and real-time monitoring of pulse widths and pulse shapes of femtosecond lasers of different pulse widths and wavelengths.

The invention relates to a laser underwater acoustic inducing device. The laser underwater acoustic inducing device is characterized in that the laser energy is converted into the sound wave energy in a certain frequency range in water maximally by means of utilization of the super-strong absorption effect, on a specific laser wavelength, such as 2-3 micrometer laser, of an aqueous medium, and a specific laser pulse shape, so that an underwater laser acoustic inducing device with no requirements for coordination with other acoustic transducers can be formed, being very suitably applicable to an underwater mobile platform; the laser underwater acoustic inducing device can be formed by a plurality of single-wavelength lasers in the range of 2-3 micrometers; when the single-wavelength lasers work synchronously, underwater strong sound field signals can be generated easily; when the single-wavelength lasers work anachronously, underwater low audio frequency signals can be easily generated; through modification of the pulse energy or repeated frequency of the lasers, underwater bubbles with different sizes or different audio frequencies can be generated; and control of the transmission direction of the sound wave can be controlled through modification of the shape of the output end surface of a conduction fiber.

A laser pulse shape measuring system to measure the pulse shape of pulses generated by a pulsed laser. Each pulse includes a pulse width and a peak wavelength. The system includes: a beam splitter coupled to the laser to separate each of the pulses into a test pulse and a probe pulse; a pulse width compression means coupled to the beam splitter to compress the pulse width of each probe pulse; a controllable delay means to control a time offset between each test pulse and a corresponding probe pulse; a nonlinear optical medium arranged such that the test beam path and the probe beam path intersect within it to generate wavelength converted pulses corresponding to intersecting pairs of pulses; a detector coupled to the nonlinear optical medium to detect the pulse energies of the wavelength converted pulses; and a processor to determine the pulse shape of the laser pulses.

The invention discloses a femtosecond laser pulse shape measuring apparatus. In the femtosecond laser pulse shape measuring apparatus, the measured horizontally polarized space-uniform femtosecond fundamental frequency laser pulse is divided into transmitted light and reflected light after passing a spectroscope, and then the transmitted light is divided into two beams so as to be incident on a frequency doubling crystal in a horizontally symmetrical angle, and then a vertically polarized autocorrelation frequency doubling signal is generated; and the frequency doubling signal and the reflected light beam of the spectroscope are incident on a sum frequency crystal along a vertical surface to generate a double delay third order intensity related triple frequency signal so as to obtain the pulse shape information. The femtosecond laser pulse shape measuring apparatus improves the temporal resolution of the measuring technology in femtosecond laser pulse shape measurement. The femtosecondlaser pulse shape measuring apparatus has the advantages of being compact in structure, being convenient for adjustment, and being low in cost.

The invention discloses a laser pulse shape measurer based on a third-order correlation method. Measured parallel laser beams are converted into transmission light and reflection light through a light splitter, the transmission light is converted into transmission light and reflection light through a semitransparent mirror, the transmission light and the reflection light are converted into frequency doubled light through a frequency doubling crystal, the time strength information is converted into the strength autocorrelation one-dimensional space information, the frequency doubled light beam and a reflection light beam after passing through the light splitter are converted through the frequency doubling crystal to realize frequency-tripled conversion, and the time strength information is converted into the strength third-order correlation two-dimensional space information. According to the measurer, through the simple reconstruction technology, not only can the pulse width information be acquired, but also the pulse waveform information can be accurately acquired, and picosecond and femtosecond pulse waveforms can be processed. The measurer has advantages of low cost, simple structure and convenient adjustment.

The invention relates to a range finding method based on laser pulse shape leading edge detection and a system thereof and belongs to the laser pulse range finding technology field. In the invention, a high speed ADC is used to sample a reference wave and an echo of a pulse signal. A simulation waveform is converted into a digital waveform signal. And then a digital signal processing mode is used to carry out echo time delay calculating so that a distance is calculated. When a laser pulse range finding mode is used to carry out object outline scanning and during a high-speed dynamic scanning process, monopulse echo range finding precision is increased and high-precision outline scanning is realized.

A programmable tailored laser pulse generator including a pulsed seed laser source, a laser amplifier, and an optical power amplifier produces high power tailored laser pulses shaped in response to a programmable analog tailored pulse signal applied to a seed laser (first embodiment) or an external modulator of continuous-wave seed laser output (second embodiment). The programmable analog tailored pulse signal is generated by combining multiple individually programmable analog pulses generated by a multi-channel signal generator. A bias applied to the pulsed seed laser source generates pre-lasing prior to producing a tailored laser pulse so that the seed laser source spectral line and line width stabilize within a narrow gain line width of a solid-state laser amplifier, thereby to impart pulse peak stability of the laser output. The tailored laser pulse generator allows for generating harmonics at shorter wavelengths and provides an economical, reliable laser source for a variety of micromachining applications.

A pulse shaping apparatus for shaping an input optical pulse into an output optical pulse having substantially constant optical power, includes a modulator that acts upon the input optical pulse in response to a control signal. A sampling unit samples a portion of the input or output pulse and generates a sample signal that corresponds to the optical power of the input or output optical pulse. In a preferred embodiment, the sampling unit includes a power splitter that splits off sample portion of the input or output pulse, and directs the sample portion to the photodetector which generates the sample signal. Processing of the sample signal may be performed in either an analog or digital form.

A programmable tailored laser pulse generator including a pulsed seed laser source, a laser amplifier, and an optical power amplifier produces high power tailored laser pulses shaped in response to a programmable analog tailored pulse signal applied to a seed laser (first embodiment) or an external modulator of continuous-wave seed laser output (second embodiment). The programmable analog tailored pulse signal is generated by combining multiple individually programmable analog pulses generated by a multi-channel signal generator. A bias applied to the pulsed seed laser source generates pre-lasing prior to producing a tailored laser pulse so that the seed laser source spectral line and line width stabilize within a narrow gain line width of a solid-state laser amplifier, thereby to impart pulse peak stability of the laser output. The tailored laser pulse generator allows for generating harmonics at shorter wavelengths and provides an economical, reliable laser source for a variety of micromachining applications.

The invention discloses a plasma switch for laser pulse shaping. The background gas of the plasma switch is mixed with easily ionized gas, and the plasma switch enables the gas to flow continuously and is provided with a cooling device. The easily ionized gas is triethylamine. The switch concretely comprises a vacuum chamber, a first lens, a second lens, a fan and a heat exchanger, wherein the first lens, the second lens, the fan and the heat exchanger are located in the vacuum chamber; the first and second lenses are the same ZnSe lenses; the vacuum chamber is formed with two inspection windows which are opposite to each other and are used for inputting and outputting laser; the centers of the two inspection windows of the vacuum chamber and the centers of the first and second lenses are located on the same straight line; the distance between the two lenses is 2f, wherein f is the focus of the lens. Compared with the prior plasma switch, the plasma switch for laser pulse shaping has advantages that the pulse width is lowered based on guaranteeing the relative high laser transmittance, and accordingly the output pulse has relative high peak power, and the repetitive rate of the device is improved.

Provided is a miniaturized linear femtosecond laser pulse shape and width measurement device, which comprises a four-hole diaphragm plate, an attenuation time-delay sheet, a first convex lens, a third-order non-linear medium, a second convex lens, an optical fiber coupler, a single-mode fiber and a spectrometer, which are arranged in sequence in the beam incident direction of a pulse to be measured. Interference fringes are subjected to analysis and processing through a Fourier transform spectral interference method to reconstruct spectral and phase information of the light to be measured, thereby restoring shape and phase of the pulse to be measured and realizing measurement of shape and width of the femtosecond pulse. The device is based on the characteristic of rectilinear propagation of the light, and has the advantages of being compact in structure, firm and easy to adjust.

The invention discloses a transient grating effect based femtosecond laser pulse measuring device. The transient grating effect based femtosecond laser pulse measuring device is characterized in that incident to-be-measured laser pulses are divided into four beams, the three beams generate self-reference light through a transient grating effect of three-phase nonlinear mediums, the three beams and the fourth beam of to-be-measured light are superposed in space and focused into a spectrometer to enable self-reference interference spectrums to be obtained, femtosecond laser pulse shapes, laser spectrums and spectrum phases are calculated through a self-reference spectrum coherent method due to measurement of interference spectrums. The transient grating effect based femtosecond laser pulse measuring device has the advantages of being compact and stable in structure and miniaturized in integrity due to the fact that a focusing system is formed by a concave mirror and a convex mirror or a plane mirror and the concave mirror and not needing an optical polarization element and being applied to femtosecond laser optical systems with the spectrum and the pulse width to be respectively from 200 to 3000nm and 10 to 300fs.

A laser pulse shaper device includes shaper unit including first dispersive element for spatially separating spectral components of laser pulses, second dispersive element for parallelizing and deflecting spectral components into Fourier plane of dispersive elements, and mirror for back-reflecting of laser pulses via dispersive elements, and light modulator in Fourier plane of dispersive elements, which is capable of modulating spectral components of laser pulses, wherein beam path of shaper unit includes forward beam path from first dispersive element via second dispersive element to mirror and return beam path from mirror via second dispersive element to first dispersive element, and focusing device is arranged at input side of forward beam path before first dispersive element for focusing spatially separated spectral components of laser pulses to Fourier plane of dispersive elements. Furthermore, a method for stretching or compressing laser pulses is described.

Laser pulse shaping techniques produce tailored laser pulse spectral output. The laser pulses can be programmed to have desired pulse widths and pulse shapes (such as sub-nanosecond to 10 ns-20 ns pulse widths with 1 ns to several nanoseconds leading edge rise times). Preferred embodiments are implemented with one or more electro-optical modulators receiving drive signals that selectively change the amount of incident pulsed laser emission to form a tailored pulse output. Triggering the drive signal from the pulsed laser emission suppresses jitter associated with other stages of the link processing system and substantially removes jitter associated with pulsed laser emission build-up time.

The invention provides a rapid fluorescence lifetime imaging system and method for flow field diagnosis, and solves the problems of low imaging time resolution and low frame rate of the existing fluorescence lifetime imaging technology. The system comprises a pulse laser, a sheet light shaping device, a flow field generating device, a filter, a framing camera and a data processing device, the pulse laser emits laser pulses and electric signals at the same time, and the sheet light shaping device is used for shaping the laser pulses into sheet light. The flow field generating device is used forproviding a to-be-detected target flow field, and the to-be-detected target flow field emits a fluorescence signal after being irradiated by sheet light; the filter is used for transmitting the fluorescence signal and filtering a spurious signal; the framing camera comprises a synchronous control device and four gating cameras, and the synchronous control device controls exposure time gates and delays of the four gating cameras; the electric signals trigger the framing camera to expose to obtain a four-framing image; and the data processing device is used for receiving the four-framing imagecaptured by the framing camera and processing the four-framing image to obtain a fluorescence lifetime image and displaying the fluorescence lifetime image.

The embodiment of the invention provides a time domain waveform-controllable laser generation system. The time domain waveform-controllable laser generation system comprises a frequency shift system,an optical fiber amplifier, a mode matcher, a solid amplifier and a feedback device, wherein the frequency shift system is connected with the optical fiber amplifier and is used for receiving laser and modulating a frequency of the laser in a real time, the optical fiber amplifier is connected with the mode matcher and is used for amplifying a power of the laser, the mode matcher is connected withthe solid amplifier and is used for performing mode matching on the laser after power amplification and pumping light in the solid amplifier, the solid amplifier is connected with the feedback deviceand is used for performing power amplification on the laser of the mode matcher after mode matching and outputting time domain waveform-controllable laser, and the feedback device is connected with the frequency shift system and is used for converting a light signal to an electrical signal and sending the electrical signal to the frequency shift system. The embodiment of the invention also provides a time domain waveform-controllable laser generation method which is implemented by the system. By the time domain waveform-controllable laser generation system, the laser frequency can be effectively modulated, and laser pulse shape conforming to requirement is acquired.

The invention provides a wavelength selection method and a communication device. The method is applied to the fields of optical communication, optical switching, digital center networks, microwave photonics, liquid crystal antennas, optical phased arrays, beam forming, beam scanning, laser radars, laser projection, laser televisions, holographic display, adaptive optics, laser beam shaping, laser processing, ultrafast laser pulse shaping, laser active imaging, optical tomography, retina imaging and the like. And under the condition that the port of the WSS device is switched, only the image data of the changed local image in the LCOS image is updated by taking the time interval smaller than the duration of one frame of image as a unit, and the driving voltage of the pixels on the LCOS display screen is refreshed according to the priority. Compared with refreshing the image data of the whole LCOS image according to the frame frequency and refreshing the driving voltage of the pixels according to the fixed sequence of the pixel numbers, the port switching of the WSS device can be accelerated.

The invention provides a miniaturized total-reflection type femtosecond laser pulse shape measurement device. A reflection type element is used before signal light is generated, so that measurement errors caused by the fact that a transmission type element introduces chromatic dispersion is avoided and the limitation of bandwidth is avoided; a light path structure of the device has a compact and stable structure, is small and firm and is easy to adjust. The principle of the measurement device adopts a self-reference spectral interference method; a transient-state grating signal is obtained byutilizing a three-order non-linear effect of materials including a glass thin sheet and the like and is used as self-reference light; the self-reference light and delayed light to be detected are subjected to spectral interference to obtain spectral interference stripes; spectrum and phase information of the light to be detected are reconstructed by carrying out analysis treatment on the interference stripes through methods including Fourier transform spectral interference and the like, so that a pulse shape to be detected and a phase are restored and measurement of femtosecond pulse shapes and widths is realized.