Abstract:
Systems and methods determining amplitude and phase versus frequency of an incoming beam of pulsed laser light. An apparatus is set to an initial configuration to split the incoming beam into two beams of substantially equal intensity, delay one of the two split beams for a delay period t and recombine the two split beams to form a recombined beam. The recombined beam shines onto a thick SHG crystal at rotation angle ? and light emitted from the thick SHG crystal is detected as data and stored with reference to the delay period t and the angle ?. The thick SHG crystal is rotated by an angle d? and the steps of splitting, delaying, recombining, shining, detecting, storing, and rotating are repeated until the thick SHG crystal has completed 360° of rotation. The delay period is increased by dt and the steps of splitting, delaying, recombining, shining, detecting, storing, rotating, repeating and increasing are repeated until a selected beam delay period range has been completed. The stored data is processed to determine amplitude and phase versus frequency of the incoming beam of pulsed laser light.
Abstract:
An optical system comprising: a nonlinear material having a ferroelectric domain structure, the nonlinear material capable of converting first and second optical signals respectively to first and second frequency-converted optical signals; and alignment means for respectively aligning the first and second optical signals such that they propagate collinearly, but in opposite directions, through the nonlinear medium to obtain a overlap region in the nonlinear material where the first and second optical signals overlap, wherein the nonlinear material being capable of converting the first and second optical signals to a third frequency converted optical signal in the overlap region; wherein the third optical frequency generated by the nonlinear material propagates in a direction that is either oblique or transverse to the propagation direction of both the first and second optical signals.
Abstract:
L'invention concerne un dispositif (150) d'échantillonnage optique hétérodyne équipé de deux sources laser impulsionnelles (10, 15) susceptibles de présenter de la gigue, aptes à émettre respectivement un faisceau «pompe» et un faisceau «sonde» de fréquences de répétition respectives Fs et Fp avec Fs≠Fp, d'un élément de combinaison (20) des faisceaux «pompe» et «sonde» destinés à être envoyés sur un échantillon (200) et qui comprend une voie signal (51) comportant un système de photo détection (50) du signal de réponse de l'échantillon, et un système d'acquisition (70) du signal photo détecté, relié à la voie signal. Fs et Fp étant sensiblement constantes, le système d'acquisition comportant un élément (71) de déclenchement de l'acquisition, il comprend reliée à cet élément de déclenchement, une voie synchronisation (90) comportant un dispositif (91) de mesure de la fréquence de battement |Fs-Fp| apte à générer un signal de synchronisation comportant des impulsions à chaque fois que les impulsions des faisceaux «pompe» et «sonde» coïncident.
Abstract:
A control system and apparatus for use with an ultra-fast laser is provided. In another aspect of the present invention, the apparatus includes a laser, pulse shaper, detection device and control system. A multiphoton intrapulse interference method is used to characterize the spectral phase of laser pulses and to compensate any distortions in an additional aspect of the present invention. In another aspect of the present invention, a system employs multiphoton intrapulse interference phase scan. Furthermore, another aspect of the present invention locates a pulse shaper and/or MIIPS unit between a laser oscillator and an output of a laser amplifier.
Abstract:
Apparatus for determining the pulse width of ultra-short light pulses of an input repetitive light pulse signal comprises a two-photon absorption. detector (2) in the form of a microcavity (3) having an active region (4) located between top and bottom distributed Bragg reflectors (5,6). An optical fibre cable 16 directs the input light pulse signal combined with a reference repetitive light pulse signal normal to an incident surface (8) of the detector (2). The input light pulse signal is split in a polarisation light splitter (19) to form the reference light pulse signal which is passed through a delay line (23) to a polarisation light combiner (20) to be combined with the input light pulse signal, and directed at the incident surface (8) by the optical fibre cable (16). The delay line (23) is operated for alternately bringing the respective light pulses of the input and reference light pulse signals into and out of phase with each other to produce a pulsed photocurrent in the microcavity (3). A monitoring circuit (14) monitors the pulsed photocurrent, and the pulse width of the light pulses is determined as the full width half maximum of the pulsed photocurrent trace. By varying the angle of incidence at which the input and reference light pulse signals are incident on the incident surface (8), the apparatus is tuneable to input light pulse signals of different wavelengths within a predetermined range of wavelengths.
Abstract:
A femtosecond laser based laser processing system having a femtosecond laser, frequency conversion optics, beam manipulation optics, target motion control, processing chamber, diagnostic systems and system control modules. The femtosecond laser based laser processing system allows for the utilization of the unique heat control in micromachining, and the system has greater output beam stability, continuously variable repetition rate and unique temporal beam shaping capabilities.
Abstract:
An optical/analog/digital pulse detector receives an input signal and drives a Bragg cell illuminated by a collimated light beam. The Bragg cell spatially modulates the collimated light beam and upon exiting the Bragg cell is imaged by lenses of an optics network to the plane to an opaque plate. A binary optical plate replicates the image of the Bragg cell on the opaque plate. The opaque plate contains slits of various lengths located where the images of the Bragg cell are replicated. To obtain the power spectrum of each of the images on the opaque plate an anamorphic lens is positioned in the path of light passing through the opaque plate. Light passing through the anamorphic lens is sensed by a detector array having outputs coupled to a focal plane processor that processes the analog outputs from the detector array into initial tuning commands for detection and characterization of pulses in the input signal.
Abstract:
A system that measures a segment of a waveform by isolating the segment by virtue of gating. A waveform anomaly may be gated. The gated waveform is supplied to a plurality of frequency information extractors, which yield information regarding the frequency content of the gated waveform at individual frequencies. Distortion introduced into the gated waveform may be measured by applying the same gating function to a reference wavefonn. The system may measure or gate an incoming waveform at time intervals dictated by a clock signal recovered from the incoming waveform. A segment of the waveform to be measured may be circulated through a fiber loop, with a fraction of the circulated signal split off for presentation to a measurement system with each circulation. The point in time at which the waveform crosses a threshold may be determined by straddle sampling.