128 results about "Pulse stretcher" patented technology

Various embodiments described herein relate to a laser source for producing a pulsed laser beam comprising a plurality of ultrashort optical pulses having a variable repetition rate. In one embodiment, the laser source comprises a fiber oscillator, which outputs optical pulses and a pulse stretcher disposed to receive the optical pulses. The optical pulses have an optical pulse width. The pulse stretcher has dispersion that increases the optical pulse width yielding stretched optical pulses. The laser source further comprises a fiber amplifier disposed to receive the stretched optical pulses. The fiber optical amplifier has gain so as to amplify the stretched optical pulses. The laser source includes an automatically adjustable grating compressor having dispersion that reduces the optical pulse width. The grating compressor automatically adjusts this dispersion for different repetition rates.

A pulse-stretcher has an optical delay loop including a beamsplitter. The beamsplitter divides an input pulse into a temporal sequence of pulse replicas, a first of which is transmitted by the beamsplitter and the remainder of which are reflected by the beamsplitter along the path of the transmitted replica. The sequence of replicas form an initially stretched pulse having a longer duration and lower peak power than the input pulse. A prism cooperative with the delay loop reflects the initially stretched pulse back into the delay loop along a path laterally displaced from the replica path. The beamsplitter divides the initially stretched pulse into a temporal sequence of pulse replicas propagating along a common path to form a finally stretched pulse, having a longer duration and a lower peak power than the initially stretched pulse. The finally stretched pulse has a sequence of power peaks. Peak power in the pulse is minimized when the beamsplitter reflectivity is selected such that the power of the first two of these peaks is equal.

The invention relates to a new method for measuring an ultrashort light pulse spectral phase in the field of information optoelectronics and a device thereof. According to the method, a time delay minus T with polarity is introduced between two quasi-monochromatic light components with frequency Omega generated by the chirped stretching of a pulse to be detected; an additional time delay plus T, which is introduced between two quasi-monochromatic light components due to a pulse stretcher, is compensated to be in synchronization with the pulse to be measured and generate two sum frequency lights together with the pulse through a sum frequency crystal; respective power spectra and coherent spectra without interference fringe are acquired through a spectrometer. The phase difference between the two sum frequency lights is calculated by the three spectra through formulae. A spectrum phase curve of the pulse to be measured is calculated by adopting a concatenated method. The method can accurately determine the phase difference polarity of the pulse spectrum, and provide the simple, real-time, rapid and accurate measurement method and the device thereof for measuring the ultrashort optical pulse spectral phase.

The invention provides a single-shot laser pulse detection device. The single-shot laser pulse detection device comprises a detection light path for transmitting baseband detection light pulses, a reference light path for transmitting frequency-doubled reference light pulses, a dual-pulse generator for obtaining dual-pulses having a first time delay and transmitted collinearly along the reference light path, a light pulse converter for converting the dual-pulses into a series of dual-pulse form sub-pulses mutually delayed in time, separated from each other in space and propagated in parallel basically, a pulse stretcher for translating each frequency component of the baseband detection light pulses so as to stretch in the time domain, a dispersor for separating the frequency components in the baseband detection light pulses in space, and a plane detector for generating third-order mutual-correlation pulse signals from the baseband detection light pulses and the sub-pulses from the dispersor. The single-shot laser pulse detection device is capable of accurately measuring the waveform of the femtosecond petawatt lase pulses and solving the problem of difficult diagnosis of ultrafast and ultrastrong pulses large in dynamic range.

A method is provided for reducing crosstalk from four-wave mixing in optical networks. Return-to-zero optical pulses are stretched in time using a pulse stretcher and launched into a transmission fiber. The transmitted signal is recompressed using a pulse compressor prior to detection and electrical filtering. The resulting reduction in peak power of the transmitted pulses and the spectral broadening of the four-wave mixing products limits the crosstalk due to four-wave mixing and enhances the system performance.

The invention discloses a method for improving a signal-to-noise ratio of femtosecond laser by using chirp matched optical parametric chirped pulse amplification and a device thereof, which belong to the technical field of ultra-short pulses. The method comprises the following steps of: firstly, stretching the femtosecond laser with a signal-to-noise ratio to be improved output by a femtosecond laser light source into chirp signal light; secondly, performing high magnification on a signal and performing low magnification on a noise by using the chirp matched optical parametric chirped pulse amplification so as to improve the signal-to-noise ratio of the chirp signal light; and finally, compressing the chirp signal light into femtosecond laser with a high signal-to-noise ratio by using an optical pulse compressor. The device for implementing the method comprises a femtosecond laser light source, a femtosecond laser, a first non-linear optical crystal, a second non-linear optical crystal, a first light pulse stretcher, a second light pulse stretcher, an optical pulse amplifier, an optical pulse compressor, a first dichroic mirror and a second dichroic mirror. The method and the device of the invention can not only improve the signal-to-noise ratio of the femtosecond laser effectively, but also realize high-efficient amplification of the femtosecond laser.

The present invention provides a modular high repetition rate ultraviolet gas discharge laser light source with a beam delivery to a production line machine. The system includes an enclosed and purged beam path with beam pointing control for delivery the laser beam to a desired location such as the entrance port of the production line machine. Preferred embodiments include equipment for beam attenuation, equipment for automatic feedback beam alignment and equipment for accurate optics module positioning at installation and during maintenance. In preferred embodiments, the production line machine is a lithography machine and two separate discharge chambers are provided, one of which is a part of a master oscillator producing a very narrow band seed beam which is amplified in the second discharge chamber. This MOPA system is capable of output pulse energies approximately double the comparable single chamber laser system with greatly improved beam quality. A pulse stretcher more than doubles the output pulse length resulting in a reduction in pulse power (mJ/ns) as compared to prior art laser systems. This preferred embodiment is capable of providing illumination at a lithography system wafer plane which is approximately constant throughout the operating life of the lithography system, despite substantial degradation of optical components.

A pulse stretcher includes a single pass pulse stretcher. An optical system is arranged around the single pass pulse stretcher. A beam enters the single pass stretcher and is reflected in a helical path using the optical system for multiple passes through the single pass pulse stretcher. The single pass pulse stretcher can include two 90° prisms, with a beam splitter located therebetween. The optical system can include first and second prisms. At least one of the first and second prisms can be a roof prism. The first and second prisms can have at least one surface oriented so as to direct the beam into the helical path. The optical system can have at least one mirror, or a plurality of mirrors.

The invention discloses a chirped pulse velocity interferometer. In the chirped pulse velocity interferometer, broadband laser pulses output by a broadband pulse laser light source are changed into linear polarization linear chirped pulses after passing through a polarizer and a pulse stretcher; polarization light S and polarization light P which are perpendicular in polarization direction are produced after the linear chirped pulses pass through a polarization splitting prism, and then the polarization light S and the polarization light P are successively emitted into the surface of a tested sample; the beat-wave interferometry is conducted on reflected light at a certain included angle, and produced beat-wave interferometric fringes are recorded through an imaging type spectrometer. A certain delay time difference exists before the polarization light S and the polarization light P are emitted into the surface of the sample, and synchronous transmission is achieved through optical path compensation after the polarization light S and the polarization light P are reflected by the surface of the sample. The oscillation penetrating direction of the polarizer is perpendicular to that of an analyzer. By means of the chirped pulse velocity interferometer, the time distinguishing of sub-picosecond scale can be achieved, the imaging type spectrometer serves as the corresponding recording system, an expensive streak camera recording system is avoided, and therefore the cost of a test system is effectively controlled.

A device generating supershort-superhigh laser pulse line of highly repeated frequency consists of self mode locking iiwaarite laser oscillator of mode locking pulse line, Faraday light isolator, aberration free laser pulse stretcher, regeneration amplifier of iiwaaeite, quantity selector of laser pulse, multistroke iiwaarite laser amplifier chain, gating pair pulse compressor in pumping laser and vacuum chamber. It is featured as exerting the first and the second DC high voltage signals on electrodes of Pochels box on amplifier, using a synchronous signal to control the first and the second DC high voltage source to work separately.

The system is composed of the laser oscillator in femtosecond level, the pulse stretcher of grating pair, the pulse shortener of grating pair, the beam splitter, the first stage OPA amplifier, the back stage OPA amplifier, the prime amplifier of pump source system, the first double frequency crystal, the dichroism spectroscopic plate etc. the characters of the invention are that the signal light and the pump light source are come from the same laser oscillator. The accurate time synchronization between the signal light pulse and the pump light pulse can be realized and the time jitted is reduced without need of the additional collimation light source. That is to say the signal light of each optical parameter amplification stage and the pump light can be collimated and synchronous adjusted.

The invention relates to a method for increasing the signal to noise ratio of a femtosecond laser through an F-P (Fabry-Perol) etalon internally installed with an electro-optic crystal and a device thereof, which belong to the technical field of ultrashort pulses. The method comprises the following steps: firstly, stretching a femtosecond laser pulse to be increased in the signal to noise ratio, which is output from a femtosecond laser light source, into chirp signal light; enabling an instaneous spectral filtering function output by the F-P etalon to be consistent with the chirp size of the chirp signal light by modulating the voltages of both ends of the electro-optic crystal internally installed in the F-P etalon, and thereby, a chirp signal pulse efficiently pass, whereas noise is filtered off to achieve the goal of increasing the signal to noise ratio of the chirp pulse; finally, compressing the chirp signal light into the femtosecond laser with higher signal to noise ratio. The device for realizing the method comprises the femtosecond laser light source, a laser pulse stretcher, the F-P etalon, the electro-optic crystal, a high-voltage pulse power supply, a laser pulse compressor and the like. The signal to noise ratio of the femtosecond laser can be effectively increased by adopting the method and the device. Moreover, the device has simple structure and convenient adjustment.