A three-dimensional imaging system and method are provided. The three-dimensional imaging system includes: an ultrashort pulse laser light source configured to generate a detection beam; a supercontinuum spectrum generator configured to generate a supercontinuum spectrum based on the detection beam passing through the supercontinuum spectrum generator; a pulse separation delayer configured to generate a continuous pulse sequence of different wavelengths with a time interval based on the supercontinuum spectrum; a multi-frequency pulse interference fringe generator configured to generate multi-frequency interference fringe patterns of different wavelength ranges with a time interval based on the continuous pulse sequence; and an image acquisition device configured to acquire an optical signal reflected by a sample irradiated by the multi-frequency interference fringe patterns to obtain a three-dimensional topography of the sample.

The application discloses an atom interferometer comprising an optical cavity and method of operation thereof. The atom interferometer includes a vacuum chamber, an optical cavity, a source for providing a cloud of atoms in the optical cavity in use, and one or more light sources. The one or more light sources are for generating, in the cavity, in use a first light beam having a first polarisation and at a first frequency for a two-photon interaction in the atoms; and a counterpropagating second light beam having a second polarisation orthogonal to the first polarisation and at a second frequency for the two-photon interaction in the atoms. The atom interferometer also includes an electro-optic element arranged in the cavity to be operable to simultaneously change: the resonant frequency of the cavity for light in the first polarisation to track changes in the frequency of the first light beam to compensate for the doppler shift of the falling atoms in use; and the resonant frequency of the cavity for light in the second polarisation to track changes in frequency of the counterpropagating second light beam to compensate for the doppler shift of the falling atoms in use.

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.

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 vibration measurement device 10 includes an excitation unit (signal generator 11 and vibrator 12) for exciting an elastic wave to an inspection target S, an illumination unit (wavelength stabilized laser beam source 13 and illumination light lens 14) for performing stroboscopic illumination to a measurement region of a surface of the inspection target S using a wavelength stabilized laser beam source 13, a displacement measurement unit (speckle-sharing interferometer 15) for collectively measuring a displacement of each point of the measurement region in the back-and-forth direction by speckle interferometry or speckle-sharing interferometer. By using the wavelength stabilized laser beam source 13, an interference image can be obtained even when the inspection target S has large surface irregularities.

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.

The invention relates to a method and system for monitoring at least one parameter of an object. There is provided an imaging system for monitoring at least one parameter of movement of a moving object, the system comprises at least one imaging unit comprising an optical transformer configured and operable for applying spatial image space transformation of at least one parameter of movement into geometric relation, by translating different components of six degrees of freedom of movement in a three-dimensional space into a lateral translation; wherein the imaging unit is configured and operable for imaging the moving object on an image plane and generating image data indicative of the moving object in an x-y plane; the imaging system generating motion data indicative of the six degrees of freedom of movement.

A fiber optic sensor arrangement is disclosed that includes a plurality of optical fiber based sensor elements, the sensor elements configured to modify an associated optical carrier signal in accordance with changes in a sensed quantity at a location of the sensor element and a phase modulation arrangement for phase modulating each optical carrier signal in accordance with respective uncorrelated pseudorandom binary sequence signals. The sensor arrangement also includes an interferometer module for receiving each of the phase modulated optical carrier signals, the interferometer module operable to convert a change in the phase modulated optical carrier signals to a change in optical intensity of the corresponding optical carrier signal to generate a combined modulated optical intensity signal, an optical intensity detector for measuring the combined modulated optical intensity signal and generating a time varying electrical detector signal and an analog to digital convertor to convert the time varying electrical detector signal to a time varying digitized detector signal. Also included in the sensor arrangement is a decorrelator arrangement for decorrelating the time varying digitized detector signal against the respective uncorrelated pseudorandom binary sequence corresponding to each of the optical carrier signals to recover each of the modulated optical carrier signals and a demodulator for demodulating each of the modulated optical carrier signals to recover the respective optical carrier signal to determine the changes in the sensed quantity at the location of the sensor element.

A coherence gated photoacoustic remote sensing system for imaging a subsurface structure in a sample with optical resolution may include an excitation beam source configured to generate an excitation beam that induces ultrasonic signals in the sample at an excitation location; an interrogation team source configured to generate an interrogation team incident on the sample at an interrogation location, a portion of the interrogation beam returning from the sample that is indicative of the generated ultrasonic signals, the interrogation beam being a low-coherent beam; an optical system that focuses the excitation beam onto the sample at an excitation location, and focuses the interrogation beam onto the sample at an interrogation location, at least the interrogation location being below the surface of and within the sample; and a low coherence interferometer that isolates a returning portion of the interrogation beam that corresponds to an interrogation event of the sample.