An apparatus can be provided which can include a laser arrangement which can be configured to provide a laser radiation, and can include an optical cavity. The optical cavity can include a dispersive optical first arrangement which can be configured to receive and disperse at least one first electro-magnetic radiation so as to provide at least one second electro-magnetic radiation. Such cavity can also include an active optical modulator second arrangement which can be configured to receive and modulate the at least one second radiation so as to provide at least one third electro-magnetic radiation. The optical cavity can further include a dispersive optical third arrangement which can be configured to receive and disperse at least one third electro-magnetic radiation so as to provide at least one fourth electro-magnetic radiation. For example, actions by the first, second and third arrangements can cause a spectral filtering of the fourth electro-magnetic radiation(s) relative to the first electro-magnetic radiation(s). The laser radiation can be associated with the fourth radiation(s), and a wavelength of the laser radiation can be controlled by the spectral filtering caused by the actions by the first, second and third arrangements.

Various optical systems equipped with diode laser light sources are discussed in the present application. One example system includes a diode laser light source for providing a beam of radiation. The diode laser has a spectral output bandwidth when driven under equilibrium conditions. The system further includes a driver circuit to apply a pulse of drive current to the diode laser. The pulse causes a variation in the output wavelength of the diode laser during the pulse such that the spectral output bandwidth is at least two times larger the spectral output bandwidth under the equilibrium conditions.

A shape measurement method of the present invention includes: a step of irradiating a measurement object with an optical pulse train in which a plurality of optical pulses that have predetermined frequency distributions on a time axis are disposed chronologically in numerical order; and a step of measuring an optical shape of the measurement object in accordance with a correspondent relation between numbers of the optical pulses of a plurality of detection target optical pulse trains after the emitted optical pulse train acts on the measurement object and a correspondent relation between the frequency distributions in the optical pulses.

A system and a method determines a traveling time for a light pulse between a light pulse source and a pixel of a light sensor array based on a Find Frequent Items in a Data Steam technique. In one embodiment, raw timestamp data output from a pixel as a data stream may be temporarily stored, processed twice and then discarded to provide an exact determination of a traveling time estimate. In another embodiment, the raw timestamp data is processed once and discarded to provide an approximate determination of a traveling time estimate. The traveling time estimate may be updated during processing and the most-frequently occurring timestamp is available when processing the data stream is complete. There is no need to keep the raw data in a memory, thereby reducing the memory requirement associated with determining the traveling time of a light pulse.

Systems, methods and apparatuses are used for monitoring material processing using imaging signal density calculated for an imaging beam directed to a workpiece or processing region, for example, during inline coherent imaging (ICI). The imaging signal density may be used, for example, to monitor laser and e-beam welding processes such as full or partial penetration welding. In some examples, the imaging signal density is indicative of weld penetration as a result of reflections from a keyhole floor and/or from a subsurface structure beneath the keyhole. The monitoring may include, for example, automated pass/fail or quality assessment of the welding or material processing or parts produced thereby. The imaging signal density may also be used to control the welding or material processing, for example, using imaging signal density data as feedback. The imaging signal density may be used alone or together with other measurements or metrics, such as distance or depth measurements.

An apparatus can be provided which can include a laser arrangement which can be configured to provide a laser radiation, and can include an optical cavity. The optical cavity can include a dispersive optical first arrangement which can be configured to receive and disperse at least one first electro-magnetic radiation so as to provide at least one second electro-magnetic radiation. Such cavity can also include an active optical modulator second arrangement which can be configured to receive and modulate the at least one second radiation so as to provide at least one third electro-magnetic radiation. The optical cavity can further include a dispersive optical third arrangement which can be configured to receive and disperse at least one third electro-magnetic radiation so as to provide at least one fourth electro-magnetic radiation. For example, actions by the first, second and third arrangements can cause a spectral filtering of the fourth electro-magnetic radiation(s) relative to the first electro-magnetic radiation(s). The laser radiation can be associated with the fourth radiation(s), and a wavelength of the laser radiation can be controlled by the spectral filtering caused by the actions by the first, second and third arrangements.

A system and corresponding method are presented. the system comprises: an illumination unit comprising 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 said illumination onto one or more selected inspection regions; and a collection unit comprising 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 being 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 said one or more inspection regions.

Various optical systems equipped with diode laser light sources are discussed in the present application. One example system includes a diode laser light source for providing, a beam of radiation. The diode laser has a spectral output bandwidth when driven under equilibrium conditions. The system further includes a driver circuit to apply a pulse of drive current to the diode laser. The pulse causes a variation in the output wavelength of the diode laser during the pulse such that the spectral output bandwidth is at least two times larger the spectral output bandwidth under the equilibrium conditions.

An object of the invention is to measure an outside size of the vehicle accurately while running the vehicle. A plurality of the 1st sensors 25, 26 irradiate inspection lights to a plurality of places (4a) of the vehicle 4 of a railroad and output measurement signals which show positions and distances by receiving lights from a plurality of the places of the vehicle 4. The 2nd sensor 27, 28 or 29 irradiates an inspection light to an outside surface of the vehicle 4 and outputs a measurement signal which shows a position and a distance by receiving a light from the outside surface of the vehicle 4. The control equipment 30 or the processing equipment 41 processes the measurement signals outputted from a plurality of the 1st sensors 25, 26, detects positions and heights of a plurality of the places of the vehicle 4, processes the measurement signal outputted from the 2nd sensor 27, 28 or 29, and detects the outside size of the vehicle 4. And the control equipment 30 or the processing equipment 41 calculates amounts of a deviation of the outside surface of the vehicle 4 due to a swing of the vehicle 4 based on amounts of fluctuations of the detected positions and heights of a plurality of the places of the vehicle 4, and corrects the detected outside size of the vehicle 4 according to the calculated amounts of the deviation.

A method for identifying three entangled photons includes generating a set of first, second, and third entangled photons correlated in time and interfering the first and second entangled photons based on a difference between a first optical path from an output of an optical source that generates the first entangled photon to a first optical input to an interferometric beam splitter and a second optical path from an output of the optical source that generates the second entangled photon to a second input of the interferometric beam splitter. A first electrical signal is generated in response to detection of a first photon generated by the interfering of the first and second entangled photons. A second electrical signal is generated in response to detection of a second photon generated by the interfering of the first and second entangled photons. A third electrical signal is generated in response to detection of the third entangled photon. The first photon coincidence is determined from the first, second and their electrical signals, thereby identifying three entangled photons.