Abstract: A method for validating the placement of pieces in an assembly task by scanning a coherent light source, such as a laser, over a surface and characterizing the detected interference speckle pattern to discriminate the position of the placed piece from the surface on which the piece is placed. This discrimination is possible even if the characteristic features of the piece and background are smaller than the resolution of the scanning system. In addition, characteristics of the piece, such as the orientation of fibers in the material, may be sensed by classification of the associated speckle response.

Abstract: A passive photonics reservoir computing system comprises an optical waveguide based structure comprising a plurality of discrete nodes and a plurality of passive waveguide interconnections between the nodes for propagating the at least one photonic signal between the nodes, in which each discrete node is adapted for passively relaying the at least one photonic wave over the passive waveguide interconnections connected thereto, wherein the optical waveguide based structure comprises at least one multimode Y-junction configured for connecting three waveguides using a taper section wherein the taper section is not perfectly adiabatic. A training scheme uses a passive photonics computing system.

Abstract: A high-speed device, for inspecting a large area of an object, which includes: a terahertz wave generation portion configured to generate a terahertz wave; a ring beam forming portion configured to form a ring beam by using the terahertz wave incident from the terahertz wave generation portion; a rotary mirror configured to reflect the ring beam formed by the ring beam forming portion while rotating to allow the ring beam to be incident on an inspection target object; and a detector configured to detect a ring beam generated from the inspection target object.

Abstract: An object detection training method can include receiving a training sample set in a current iteration of an object detection training process over an object detection neural network. The training sample set can include first samples of a first class and second samples of a second class. A first center loss value of each of the first and second samples can be determined. The first center loss value can be a distance between a feature vector of the respective sample and a center feature vector of the first or second class which the respective sample belongs to. A second center loss value of the training sample set can be determined according to the first center loss values of the first and second samples. A first target loss value of the current iteration can be determined according to the second center loss value of the training sample set.

Abstract: An apparatus includes a light source to provide a plurality of input optical modes in a squeezed state. The apparatus also includes a network of interconnected reconfigurable beam splitters (RBSs) configured to perform a unitary transformation of the plurality of input optical modes to generate a plurality of output optical modes. An array of photon counting detectors is in optical communication with the network of interconnected RBSs and configured to measure the number of photons in each mode of the plurality of the output optical modes after the unitary transformation. The apparatus also includes a controller operatively coupled to the light source and the network of interconnected RBSs. The controller is configured to control at least one of the squeezing factor of the squeezed state of light, the angle of the unitary transformation, or the phase of the unitary transformation.

Abstract: A first light source outputs measurement light having a wavelength in infrared range. A second light source outputs guide light having a wavelength in visible range. A fiber coupler includes a first port into which the measurement light is input, a second port into which the guide light is input, and a third port outputting combined light formed by combining the measurement light and the guide light with each other. A measurement unit emits the combined light to a measurement object and receives return light reflected therefrom. A processing unit obtains information relating to a distance, a speed, or an oscillation of the measurement object, based on an interference signal of the return light and the reference light. The fiber coupler is formed by a single mode fiber that has a cutoff wavelength that is shorter than that of the measurement light and longer than that of the guide light.

Abstract: Systems for confocal Raman spectroscopy of points of interest or regions of interest with concurrent imaging are disclosed. The imaging may be used for real time selection of points of interest or regions of interest for Raman spectroscopy and to monitor for unwanted motions of a sample while Raman spectra are acquired. Disclosed embodiments apply Reflectance confocal microscopy (RCM) in a confocal Raman spectroscopy system. A single laser may be used as a light source for both RCM and micro-Raman spectroscopy. A Faraday optical isolator may be applied to extract RCM signals for imaging Systems as described herein have example application for ex vivo sample and in vivo skin measurement.

Abstract: The invention provides a wavelength tracking system comprising a wavelength tracking unit and an interferometer system. The wavelength tracking unit has reflection surfaces at stabile positions providing a first reflection path with a first path length and a second reflection path with a second path length. The first path length is substantially larger than the second path length.

Abstract: Methods and devices are described for performing an all-phase measurement of an ultra-fast laser pulse having a spectral range of greater than one octave. The ultra-fast laser pulse may be split into a first beam comprising a fundamental light with a wavelength ?0 and a second beam comprising a light with a wavelength 2?0. The light with the wavelength 2?0 may be frequency doubled to a light with a wavelength ?0 to generate an interference with the fundamental light. Fourier transform may be performed on an interference spectrum of the interference, and a relative envelope delay (RED) between the fundamental light and the frequency doubled light and a carrier envelope phase (CEP) may be acquired based on a result of the Fourier transform.

Abstract: The invention relates to the technical field of mechanical vibration measurement, and discloses a device for accurately measuring mechanical vibration by photon counter. The device comprises a laser, an optical isolator, an adjustable attenuator, an optical fiber coupler, a single-photon counter and an FPGA post-processing module, wherein the laser enters the optical fiber coupler after passing through the optical isolator and the adjustable attenuator, and then enters into a measured object. The transmitted signal of the object to be measured returns to the optical fiber coupler and is output to the single-photon counter; the mechanical vibration of the measured object is analysed and obtained by the FPGA post-processing module connecting with the output terminal of the single-photon counter.

Abstract: A data processing device of the present invention includes: a data communication device configured to communicate with a laser radar device to acquire a value of line-of-sight wind-speed, a laser emission angle, attitude information, position information, and a time; a storage device configured to store the value of line-of-sight wind-speed and the time; a central processing unit configured to run a data selector to select a value of line-of-sight wind-speed stored in the storage device and being present within a set time period from a time about the value of line-of-sight wind-speed which is newly acquired by the data communication device, and configured to run a wind vector calculator to calculate a wind vector using the newly acquired value of line-of-sight wind-speed and using the selected value of line-of-sight wind-speed; and a memory configured to preserve the data selector and the wind vector calculator.

Abstract: Provided are an imaging apparatus capable of acquiring an image having a small transmission wavelength shift at a plurality of wavelengths and an image processing apparatus capable of measuring a subject on the basis of an image which has a small transmission wavelength shift and which is acquired at a plurality of wavelengths. High image height rays imaged at a position of which an image height is high is incident at a large angle with respect to the optical axis. Therefore, the transmission wavelength shift increases. However, in the imaging apparatus according to the first aspect, the first optical system causes the high image height rays to be incident into the first optical filter and the second optical filter in a state where the upper ray and the lower ray are parallel.

Abstract: The purpose of the present invention is to provide a device for optical frequency domain reflectometry and a method thereof that can measure a reflectance distribution with less spatial resolution degradation due to a phase noise, without using a wideband receiving system even when a long-distance measurement is performed.

Abstract: An improved technique for acoustic sensing involves, in one embodiment, launching into a medium, a plurality of groups of pulse-modulated electromagnetic-waves. The frequency of electromagnetic waves in a pulse within a group differs from the frequency of the electromagnetic waves in another pulse within the group. The energy scattered by the medium is detected and, in one embodiment, the beat signal may be used to determine a characteristic of the environment of the medium. For example, if the medium is a buried optical fiber into which light pulses have been launched in accordance with the invention, the presence of acoustic waves within the region of the buried fiber can be detected.

Abstract: A method for analyzing the wavefront effect of an optical system includes: illuminating a measurement mask (110, 310) with illumination light, producing an interferogram in a specified plane using a diffraction grating (150) from a wavefront from the illuminated measurement mask and traveling through the optical system; and capturing the interferogram with a detector (170). Different angular distributions of the illumination light incident on the measurement mask are produced via a mirror arrangement of independently settable mirror elements. A plurality of interferograms are captured in a plurality of measurement steps, wherein these measurement steps differ respectively in angular distribution of the illumination light that is incident on the measurement mask.

Abstract: An improved technique for acoustic sensing involves, in one embodiment, launching into a medium, a plurality of groups of pulse-modulated electromagnetic-waves. The frequency of electromagnetic waves in a pulse within a group differs from the frequency of the electromagnetic waves in another pulse within the group. The energy scattered by the medium is detected and, in one embodiment, may be used to determine a characteristic of the environment of the medium. For example, if the medium is a buried optical fiber into which light pulses have been launched in accordance with the invention, the presence of acoustic waves within the region of the buried fiber can be detected.

Abstract: A method comprising forming a linear temporal non-stationary amplitude filter by interacting a high intensity ultrashort laser pump pulse with a photo-excitable material, focusing an ultrashort broadband laser probe pulse over the photo-excited material, acquiring a two-dimensional spectrogram and retrieving amplitudes and phases of both temporal probe pulse and linear non-stationary amplitude filter from the two-dimensional spectrogram.

Abstract: A method of communicating through the earth which includes the steps of using a digital pulse train to generate a sweep pulse train which controls the frequency of a magnetic field at a first location, and at a second location, detecting the magnetic field and producing a signal at a frequency dependent on the frequency of the sweep pulse train, and extracting a replica of the digital pulse train from the signal.

Abstract: Systems and methods are provided for filtering coherent infrared light from a thermal background for protection of infrared (IR) imaging arrays and detection systems. A Michelson interferometer is used for coherent light filtering. In an implementation, a system includes a fixed mirror, a beam splitter, and a moving mirror which can be controlled translationally, as well as tip/tilt. The Michelson interferometer may be used as an imaging system. For imaging applications, a system may comprise a tunable array of micro-electromechanical systems (MEMS) mirrors. A mid-wave IR interferometer with electronic feedback and MEMS mirror array is provided.

Abstract: A system for registering multiple point clouds captured by an aircraft is disclosed. The system includes a speckle generator, at least one three-dimensional (3D) scanner, and a processor coupled thereto. In operation, the speckle generator projects a laser speckle pattern onto a surface (e.g., a featureless surface). The at least one 3D scanner scans the featureless surface to generate a plurality of point clouds of the featureless surface and to image at least a portion of the laser speckle pattern. The processor, which is communicatively coupled with the at least one 3D scanner, registers the plurality of point clouds to generate a complete 3D model of the featureless surface based at least in part on the laser speckle pattern.

Abstract: The present invention relates to a device, use of the device and a method for high contrast imaging, particularly suitable for imaging of moving object of interest such as gas expanding from a gas jet or physical or chemical or biological processes in material. The device for high-contrast imaging comprises a beam splitter for splitting a beam into a probe beam and a reference-beam, wherein the probe beam is directed to an object; a self-imaging system for receiving the probe beam from the object and imaging the object on itself while in a preferred embodiment, the system preserves a reflected probe beam divergence. The beam interacts with the object at least twice; and the reflected probe beam is further directed to the splitter after the last interaction; and detection means receiving the probe beam from the splitter.

Abstract: A system for imaging may include an illumination system that includes a light source to generate a light beam; and a spatial encoding pattern generator comprising one or a plurality of optical elements to encode the imaging beam so as to concurrently illuminate an object by a plurality of different spatial encoding patterns, wherein each encoding pattern of said different encoding patterns is characterized by a distinct wavelength of the imaging pattern. The system may also include an imaging sensor for receiving the encoded imaging beam transmitted through the object or reflected off the object; and a processor for decoding image data from the imaging and reconstructing an image of the object.

Abstract: There is provided system and a separation substrate device for use with an NLM separator in separating and/or detecting at least one target analyte in a sample, the substrate comprising a micromagnet array of a plurality of micromagnets, the micromagnet array comprising a first capture region, a second focusing region, and, a third detection region, the focusing region comprising a converging and/or diverging micromagnet array region. Also provided is a method for separating and detecting at least one target analyte in a sample.

Abstract: A circuit and method for mitigating multi-path interference in direct detection optical systems is provided. Samples of an optical signal having a pulse amplitude modulated (PAM) E-field are processed by generating a PAM level for each sample. For each sample, the sample is subtracted from the respective PAM level to generate a corresponding error sample. The error samples are lowpass filtered to produce estimates of multi-path interference (MPI). For each sample, one of the estimates of MPI is combined with the sample to produce an interference-mitigated sample.

Abstract: An optical analysis method and assembly for analysing an ultrashort laser pulse, the assembly includes a single-shot optical autocorrelator, having a polarity separator for angular separation of an incident laser radiation beam with fundamental frequency (?) into two laser radiation beams with the fundamental frequency and linear polarities which are orthogonal to one another, the two beams forming angle therebetween so that the beams at least partially overlap at the output of the separator, a type-II nonlinear crystal receives the at least partially overlapping beams and generates, at the output of the crystal, a single laser radiation beam with harmonic frequency (2?). A spectral filtering device selectively allows the passage of the single laser radiation beam while blocking the laser radiation beams with fundamental frequency. The non-linear crystal, spectral filtering device, and detection system detect an intensimetric single-shot autocorrelation trace of the order of two at the harmonic frequency.

Abstract: A method and system are disclosed for use in imaging a sample. The method comprises illuminating a sample through a scattering medium, or illuminating a sub-surface region of the sample through a scattering surface region of the sample, with a plurality of spatial patterns of incident electromagnetic radiation, wherein each spatial pattern of incident electromagnetic radiation interacts with the sample, or the sub-surface region of the sample, to generate electromagnetic radiation in the sample or the sub-surface region of the sample.

Abstract: A method of measuring a volume of a micro projection includes: measuring a three-dimensional shape of the micro projection using white-light interferometry; comparing a height at which a first peak of an envelope of an interference light intensity is detected with a height of a reference plane, and extracting a projection top portion of the micro projection; detecting a height of the extracted projection top portion; detecting a diameter based on a lateral dimension and a longitudinal dimension of a circumscribed quadrangle in an area that constitutes the projection top portion and a region having a height different from the height of the reference plane, the region including or being in contact with the projection top portion; and calculating the volume of the micro projection based on the height of the projection top portion and the diameter.

Abstract: An optical apparatus has an OCT imaging apparatus with a first light source for low coherence light of wavelengths above a threshold wavelength and a signal detector that obtains an interference signal between low coherence light from the sample and low coherence light reflected from a reference. A surface contour imaging apparatus has a second light source that emits one or more wavelengths of surface illumination below the threshold wavelength, a camera to acquire images from illumination reflected from the sample and a probe that has a raster scanner wherein the low coherence light and the surface illumination share the same path from the raster scanner to the sample. A processor coordinates activation of the light sources, actuation of the scanner, and acquisition of data and the camera and follows instructions to display, store, or transfer images from the acquired data.

Abstract: An optical pulse measuring method measuring an optical pulse generated from a pulse light source is provided. The method includes: splitting the optical pulse and then focusing them at a measuring point, so as to generate gas plasma by the autocorrelation of the split optical pulses; receiving the sound signal from the gas plasma and generate a plasma sound signal; and using the plasma sound signal to calculate the characteristics of the optical pulse. A measuring device is also provided.

Abstract: Apparatus and methods of full spatio-temporal characterization of ultrashort pulses from an input pulse-beam source. An interferometer system generates a first, second, third, and fourth replica of the input pulse-beam such that the second replica has a varying delay with respect to the first replica and the fourth replica has a varying delay with respect to the third replica. A reference plane is imaged onto a nonlinear spectral measurement device based upon the first and second replicas, and the reference plane is also imaged onto a wavefront sensitive (WFS) imaging element based on the third and fourth replicas. The signals from the WFS imaging element and the spectral signal are used to compute a pulse temporal spectral profile of the input pulse-beam.

Abstract: System and method for monitoring of performance of a mirror array of a digital scanner with a use of light, illuminating the mirror array at grazing (off-axis) incidence, and an optical imaging system that includes a lateral shearing interferometer (operated in either static or a phase-shifting condition) during and without interrupting the process of exposure of the workpiece with the digital scanner, to either simply identify problematic pixels for further troubleshooting or measure the exact magnitude of the deformation of a mirror element of the mirror array.

Abstract: A measurement device (100) for a golf course green comprises: a distance measurement unit (30) having a pair of laser transmitter/receivers (32) for emitting a pair of laser beams (L; L1, L2), for distance measurement, outwardly at a predetermined emission angle with respect to the forward direction (CEN); a control unit (50) for generating hole-cup position information and hole-cup gradient information from an arithmetic operation of data on the distance measured by the pair of laser transmitter/receivers (32) of the distance measurement unit (30) and data on the emission angle; and an output unit (60) provided outside a casing (10) so as to output the hole-cup position information and hole-cup gradient information generated by the control unit (50).

Abstract: A single shot autocorrelator for measuring duration of an ultrashort laser pulse in the far field, having a beam splitter to form two beams from an input ultrashort pulse: the reflected beam is firstly reflected by two mirrors mounted on a translation stage for adjusting time delay and subsequently a third mirror, and after focused by a spherical convex lens, enters a naturally grown strontium barium niobate crystal along the crystal z axis; the transmitted beam is firstly focused by a spherical convex lens, and after reflected by two mirrors, enters the crystal along the crystal z axis from opposite direction. The crystal is in the common focal regions of two spherical convex lenses and generates the transverse second harmonic pulse beam that is the autocorrelation signal to be recorded, which is imaged with an optical microscope onto a charge coupled device camera mounted perpendicular to the beams.

Abstract: The invention relates to methods and apparatus for determining properties of a surface.

Abstract: Techniques for propagating a reflection of an object. In an example, a method includes receiving an input image comprising a first reflection of a first object on a reflective surface. The method further includes generating a second reflection for a second object in the input image. The second reflection is a reflection of the second object on the reflective surface. The method includes adding the second reflection to the input image. The method includes outputting a modified image comprising the first object, first reflection, the second object, and the second reflection.

Abstract: The present application provides a spectral phase interference device and system for addressing the problem of low stability and compactness with prior art spectral phase interference devices. In the device or system provided in the present application, the optical element for generating the pulse pair to be measured consists of only a birefringent crystal and the adjustment of two-step phase shift is also completed by only a broadband quarter-wave plate. Therefore, wide application of optical elements such as pulse stretchers, retarders, optical splitters and mirrors as in prior art devices is avoided, thereby significantly simplifying the overall device's structure and resulting in enhanced stability and compactness at the same time.

Abstract: A measurement system for use in measuring parameters of a patterned sample, the system including a broadband light source, an optical system configured as an interferometric system, a detection unit, and a control unit, where the interferometric system defines illumination and detection channels having a sample arm and a reference arm having a reference reflector, and is configured for inducing an optical path difference between the sample and reference arms, the detection unit for detecting a combined light beam formed by a light beam reflected from the reflector and a light beam propagating from a sample's support, and generating measured data indicative of spectral interference pattern formed by spectral interference signatures, and the control unit for receiving the measured data and applying a model-based processing to the spectral interference pattern for determining one or more parameters of the pattern in the sample.

Abstract: An exemplary optical apparatus has an OCT imaging apparatus with a first light source for low coherence light of wavelengths above a threshold wavelength and a signal detector that obtains an interference signal between low coherence light from the sample and low coherence light reflected from a reference. A surface contour imaging apparatus has a second light source that emits one or more wavelengths of surface illumination below the threshold wavelength, a camera to acquire images from illumination reflected from the sample. The exemplary optical apparatus and/or exemplary methods for using the same can provide reduced errors in generating a dental 3D surface mesh.

Abstract: The present disclosure relates to an OCT device, which can be simply mounted without changing the structure of a microscope or an endoscope, thereby realizing an OCT system and, more particularly, to a removable OCT device including: a tunable laser configured to emit light to the light output side of an optical device by tuning the wavelength of the light; a first beam splitter installed on a path of the light emitted from the tunable laser; and a reference mirror installed on a path of the light that has passed through the first beam splitter, wherein the removable OCT device is mounted at the light output side of the optical device.

Abstract: It is provided a method for identifying optical aberrations. The method comprising the steps of providing at least one first optical beam and a second optical beam; creating a combined beam by at least partially superimposing the first and the second optical beam; focusing the combined beam into or through a medium and detecting radiation excited in the medium by the combined beam due to nonlinear optical effects; detecting the radiation excited in the medium by the combined beam for each one of the phase positions, the spatial positions and/or the time positions of the first beam; and identifying aberrations using signals generated by a detection device for the plurality of the phase positions, the spatial positions and/or the time positions of the first beam relative to the second beam upon the detection of the radiation excited in the medium.

Abstract: A computer-implemented method for analyzing digital holographic microscopy (DHM) data for hematology applications includes receiving a DHM image acquired using a digital holographic microscopy system. The DHM image comprises depictions of one or more cell objects and background. A reference image is generated based on the DHM image. This reference image may then be used to reconstruct a fringe pattern in the DHM image into an optical depth map.

Abstract: An optical coherence tomography system for imaging a sample is configured so as to illuminate a region of interest of the sample with incident light from an optical source. The optical coherence tomography system is further configured so as to interfere, on an optical detector, reference light from the optical source with offset returning light emerging from the sample along an offset collection path which is spatially offset from the region of interest of the sample, thereby creating interference on the optical detector.

Abstract: Embodiments relate to systems and methods for dissipating heat within a gas detector. A gas detector may comprise an airflow generator configured to generate a sample gas flow through the gas detector; a sample gas flow line configured to direct the sample gas flow within a housing of the gas detector from an inlet of the gas detector toward an outlet of the gas detector; a sensor, in fluid communication with the airflow generator via the sample gas flow line, configured to detect one or more potentially hazardous gases within the sample gas flow; and a heat sink, in fluid communication with the airflow generator and positioned after the sensor along the sample gas flow line, configured to transfer heat from an interior of the housing to the sample gas flow, wherein the sample gas flow is directed out of the housing via the outlet of the gas detector.

Abstract: An interferometric position sensor for sensing the position of an object is disclosed. The position sensor comprises a light source arranged to emit light, a beam splitter, and a detector array. The beam splitter is arranged to split the light between first and second optical paths, which are configured such that the split light is recombined so as to form an optical interference pattern dependent on the difference between the optical path lengths of the first and second optical paths. The detector array is arranged to measure the intensity of at least a part of the optical interference pattern. At least one of the first and second optical path lengths is arranged to be dependent on the position of the object, such that changes in the optical interference pattern can be related to changes in the position of the object.

Abstract: A system and corresponding method are presented. The system includes an illumination unit including at least one light source configured for emitting coherent illumination of one or more selected wavelength ranges having selected illumination modulation pattern and for directing the coherent illumination onto one or more selected inspection regions; and a collection unit including at least one detector array and imaging optical arrangement configured for collecting interacting light from the one or more selected inspection regions and for generating corresponding one or more sequences of image data pieces at selected sampling rate. The image data pieces are indicative of secondary speckle patterns formed in collected interacting light. The illumination modulation pattern is selected for increasing temporal bandwidth collection of speckle patterns associated with temporal shifts in the one or more inspection regions.

Abstract: The present disclosure generally relates to laser systems and laser pulse characterization methods and respective systems. An embodiment of the method comprises generating two collinear replicas of the pulse being characterized; applying two different predetermined spectral phases to each replica, so as to simultaneously scan delay and dispersion; applying a nonlinear process to the pulse to be characterized; measuring the resulting signal from the application of the predetermined spectral phases and nonlinear process; applying a numerical iterative algorithm to the measured signal to retrieve the spectral phase of the pulse to be characterized; such process being done as a scanning procedure or in parallel utilizing a single laser shot.

Abstract: A filtering device comprising first and second interference filters each comprising a Fabry-Perot cavity formed by semi-reflective layers between which a structured layer is arranged, wherein the structured layer belongs conjointly to the two filters, has a substantially constant thickness, is substantially planar and comprises two materials with different refractive indices arranged in each of the cavities, forming vertical structurings, the cavity of the second filter comprises a spacer arranged between one of the semi-reflective layers and the structured layer so that a distance between the semi-reflective layers of the cavity of the second filter is greater than a distance between the semi-reflective layers of the cavity of the first filter, and the filters comprise a second structured layer arranged in the cavities of the filters, and/or each filter comprises a second Fabry-Perot cavity comprising a third structured layer.

Abstract: A determining method comprises a first computing step implemented by a computational module to compute a static pressure from an altitude determined by a geolocation module, a receiving step implemented by a reception module to receive a static pressure determined by a static pressure sensor, a second computing step implemented by a second computational module to compute a static pressure difference between the static pressure and the static pressure, a step of filtering the static pressure difference, a third computing step implemented by a third computational module in order to compute the backup altitude from the filtered static pressure difference and from the static pressure, and a sending step implemented by a sending module in order to deliver the computed backup altitude to a user device.

Abstract: Disclosed are a pattern light irradiating device and an inspection apparatus using the same. The pattern light irradiating device includes first and second pattern light sources installed on a frame having a plurality of through-holes. Each of the through-holes is formed along a single optical axis. The first pattern light source is configured to irradiate first pattern light having a fixed pitch. The second pattern light source is configured to irradiate second pattern light having a variable pitch.

Abstract: A laser source for emitting a group of pulses, includes a primary laser source suitable for emitting at least one primary laser pulse; at least one interferometer suitable for forming, from the primary laser pulse, a plurality of secondary laser pulses, each interferometer comprising at least one delay line allowing two secondary laser pulses to be temporally separated, by a delay comprised between 50 ps and 10 ns; and a single-mode amplifying optical fiber intended to receive the secondary laser pulses, in order to form as output a group of spatially superposed pulses.