Abstract: A non-contact apparatus and method for mapping the wave profile of capillary waves on a fluid surface to determine viscosity of the fluid. Two conducting blades coupled to a sine wave generator are positioned spaced laterally above and near the surface of the fluid to generate a standing capillary wave on the fluid surface between the blades. A laterally moveable fiber optic probe is coupled to a laser to transmit laser light toward the fluid surface and to receive reflected light from the fluid surface. Part of the laser light reflects from the end of the probe and creates an interference pattern with the light reflected from the fluid surface. The light reflected from the end of the probe and from the fluid surface are combined to form an interference signal which is analyzed to obtain the amplitude of the wave directly under the probe. By moving the probe laterally, nodes on the standing wave may be detected to find the wavelength of the capillary wave.

Abstract: The invention provides an apparatus for measuring the physical properties of a sample by optically monitoring the response of the sample to illumination by ultrashort optical pulses. The apparatus is a common path optical interferometer of a Sagnac type that can measure physical properties at normal incidence, i.e., a single-arm Sagnac interferometer featuring two beam splitters. Measurement is performed in such a manner that a sample is excited by a beam of ultrashort optical pulses, and variations in intensity and phase of another optical beam are detected. This enables a wide range of measurement of physical properties such as thickness, sound velocity, and thermal properties of substances.

Abstract: Thickness of a film in a sample may be detected by directing pump laser pulses to the surface of a sample to generate an acoustic pulse in a sample. The acoustic pulse propagates downwards until it reaches an interface between the bottom of the film and a substrate and is reflected back to the top surface of the film as a first echo. A reflection of the first echo propagates downwards and is again reflected back towards the surface as a second echo. Heterodyne interferometry is used to measure the lapse of time between the first and second echos from which the thickness of the film may be determined.

Abstract: The invention provides an apparatus for measuring the physical properties of a sample by optically monitoring the response of the sample to illumination by ultrashort optical pulses. The apparatus is a common path optical interferometer of a Sagnac type that can measure physical properties at normal incidence. The interferometer is a two-arm Sagnac interferometer featuring two beam splitters. Measurement is performed in such a manner that a sample is excited by a beam of ultrashort optical pulses, and variations in intensity and phase of another optical beam are detected. This enables a wide range of measurement of physical properties such as thickness, sound velocity, and thermal properties of substances.

Abstract: An apparatus for measuring the physical properties of a sample by optically monitoring the response of the sample to illumination by ultrashort optical pulses utilizes a common path optical interferometer of a Sagnac type that can measure physical properties at normal incidence. The interferometer is a two-arm Sagnac interferometer featuring three beam splitters. A sample is excited by a beam of ultrashort optical pulses, and variations in intensity and phase of another optical beam are detected. This enables a wide range of measurement of physical properties such as thickness, sound velocity, and thermal properties of substances.

Abstract: In order to investigate and analyse vibrations of any object, light from a laser is split with part being emitted to an object and part being mixed with the light reflected from the object to create an interference signal. That interference signal is investigated to derive therefrom a signal representing the vibrations of the object If there is bulk movement of the object, the effect of that bulk movement may impose a popular shift on the reflected light. To eliminate this from the investigation of the vibrations of the object, an estimate of frequency corresponding to the effect of the bulk movement is derived from the signal, and that used to defuse a signal of reduced bandwidth encouraging the frequency due to the bulk movement and also the frequencies of vibration Thus, the vibrations can then be derived and investigated from analysis of that signal of reduced bandwidth.

Abstract: A method (1) creates charge carriers in a concentration that changes in a periodic manner (also called “modulation”) only with respect to time, and (2) determines the number of charge carriers created in the carrier creation region by measuring an interference signal obtained by interference between a reference beam and a portion of a probe beam that is reflected by charge carriers at various depths of the semiconductor material, and comparing the measurement with corresponding values obtained by simulation (e.g. in graphs of such measurements for different junction depths). Various properties of the reflected portion of the probe beam (such as power and phase) are functions of the depth at which the reflection occurs, and can be measured to determine the depth of the junction, and the profile of active dopants.

Abstract: A laser system outputs a laser light which is directed toward an object. The laser light has a frequency corresponding to the sympathetic or natural vibration frequency of molecules forming the object. The laser light is controlled so that in response to interaction with the object, the laser light forces the molecules of the object to vibrate at their sympathetic or natural vibration frequency thereby causing a thermal resistance of the object to increase whereupon a flow of thermal energy through the object is obstructed.

Abstract: An imaging system comprises an interferometer and an ultrasound console that processes signals from the interferometer into an image for display. The interferometer may include one or more multi-element photo detectors with a plurality of parallel outputs. A parallel to serial converter is provided between the parallel output of the interferometer and the input of the ultrasound console, to convert the signals provided on the parallel outputs into a serial signal for analysis by the ultrasound console. The interferometer may be selectively coupled to the ultrasound console and the system may further comprise an ultrasound device that may also be selectively coupled to the console, offering a user the option of using either the interferometer or the ultrasound device. The ultrasound console may also include two inputs, one for the interferometer and the other for the ultrasound device.

Abstract: The invention is directed to a wave characteristic adjusting device used to compensate for a wave characteristic distortion caused by the scanning motion of a probe beam of a two-wave mixing interferometer. The invention is also directed to an apparatus and method for using the wave characteristic adjusting device in a rapid scanning laser ultrasound testing device. In a rapid scanning laser ultrasound testing device, a laser pulse is directed at periodic points along a path across the surface of a manufactured object. The laser pulse initiates an ultrasonic signal associated with the manufactured object. An interferometer may be used to measure the initiated ultrasonic signal. The interferometer scans a probe beam along a path similar to the sonic initiating laser. A pulse of the probe beam is directed at the manufactured object in the vicinity of the initiating laser pulse while continuously scanning. As a result, the probe beam pulse may exhibit a Doppler shift.

Abstract: A system and method for laser light amplification provides amplification of a laser light beam emitted from a laser light source as low-amplification seed laser light signal. The low-amplification seed laser light signal is transmitted to an amplification component. The amplification component amplifies the low-amplification seed laser light signal by stimulating emissions of the population inversion provided by a pumping diode to generate an amplified laser light signal. The system and method further directs the amplified laser light signal to an output destination. The destination may be an object undergoing laser ultrasound testing. The amplified laser light may reflect with a modulation characteristic of a sound energy wave about the object. The reflected laser light may be collected by an interferometer and used in the detection and characterization of the sound energy wave.

Abstract: The invention is directed to a system and method for implementing process control for paint thickness using sonic NDE techniques. The system may, for example, generate ultrasound waves in a test object during the manufacturing process. A detector such as an interferometer may be used to detect the ultrasound waves. An interpreter or analyzer may determine the thickness and or presence of a defect from the waves. Further, the interpreter may associate the thickness measurement and/or defect with a location about an object. Then, a control system may determine and implement an appropriate control action on the process. The control action may also be associated with the location about the object.

Abstract: A nondestructive bond testing system is implemented using a pulse laser that sends a single or multiple pulse(s) of controlled magnitude and bombards an object of interest causing a thermoelastic excitation response. This excitation in turn induces an ultrasonic propagation along or through the surface material. By detecting, capturing and interpreting these thermoelastic propagation signatures, the attachment condition of the joining materials is determined. The technique is a significant improvement over traditional mechanical pull, shear or contact type techniques. The techniques are implemented in automated high speed inspection systems suitable for real time manufacturing application. Particular applications include evaluating material joining in microelectronics manufacture (such as ball bonds) and thin coating processes.

Abstract: Apparatus for producing an indication of a material property of a sheet-like material according to the present invention may comprise an excitation source for vibrating the sheet-like material to produce at least one traveling wave therein. A light source configured to produce an object wavefront and a reference wavefront directs the object wavefront toward the sheet-like material to produce a modulated object wavefront. A modulator operatively associated with the reference wavefront modulates the reference wavefront in synchronization with the traveling wave on the sheet-like material to produce a modulated reference wavefront. A sensing medium positioned to receive the modulated object wavefront and the modulated reference wavefront produces an image of the traveling wave in the sheet-like material, the image of the anti-symmetric traveling wave being related to a displacement amplitude of the anti-symmetric traveling wave over a two-dimensional area of the vibrating sheet-like material.

Abstract: The invention is directed to a system and method for implementing process control for tubing thickness using sonic NDE techniques. The system may, for example, generate ultrasound waves in a test object during the manufacturing process. A detector such as an interferometer may be used to detect the ultrasound waves. An interpreter or analyzer may determine the tubing or sheet thickness from the waves. Then, a control system may determine and implement an appropriate control action on the process.

Abstract: The invention is directed to a system and method for implementing process control for temperature of a semiconductor wafer using sonic NDE techniques. The system may, for example, generate ultrasound waves in a test object during the manufacturing process. A detector such as an interferometer may be used to detect the ultrasound waves. An interpreter or analyzer may determine the temperature of the semiconductor wafer from the waves. Then, a control system may determine and implement an appropriate control action on the process.

Abstract: A method (1) creates charge carriers in a concentration that changes in a periodic manner (also called “modulation”) only with respect to time, and (2) determines the number of charge carriers created in the carrier creation region by measuring an interference signal obtained by interference between a reference beam and a portion of a probe beam that is reflected by charge carriers at various depths of the semiconductor material, and comparing the measurement with corresponding values obtained by simulation (e.g. in graphs of such measurements for different junction depths). Various properties of the reflected portion of the probe beam (such as power and phase) are functions of the depth at which the reflection occurs, and can be measured to determine the depth of the junction, and the profile of active dopants.

Abstract: In order to probe an object in motion subject to surface displacement, for example, caused by ultrasonic wave propagation, a laser beam is split into a first portion and a second portion. The first is scatted off the object to generate a signal beam. The frequency shift produced in the signal beam due to motion of the object is measured, and this is used to adjust the frequency of one or both portions of the laser beam so that both beams have substantially the same frequency. The surface displacements are measured by comparing the second portion of the laser beam and the signal beam after frequency adjustment.

Abstract: An optical apparatus for coherent detection of an input optical beam. The apparatus includes a beam splitter for splitting the input optical beam into a first component and a second component; an optical delay device arranged to receive the second component, the optical delay device imposing an intentional delay in the second component of the input optical beam; and an adaptive beam combiner coupled to receive the second component with a delay imposed thereon by the optical delay device; and the first component from the beam splitter. The adaptive beam combiner has two exiting components: a first exiting component being representative of the difference of the first and second components received thereby and a second exiting component being representative of the sum of the first and second components received thereby. A detector arrangement is provided for receiving and detecting the first and second exiting components from the adaptive beam combiner.

Abstract: A method (1) creates charge carriers in a concentration that changes in a periodic manner (also called “modulation”) only with respect to time, and (2) determines the number of charge carriers created in the carrier creation region by measuring an interference signal obtained by interference between a reference beam and a portion of a probe beam that is reflected by charge carriers at various depths of the semiconductor material, and comparing the measurement with corresponding values obtained by simulation (e.g. in graphs of such measurements for different junction depths). Various properties of the reflected portion of the probe beam (such as power and phase) are functions of the depth at which the reflection occurs, and can be measured to determine the depth of the junction, and the profile of active dopants.

Abstract: A pump beam is modulated at a first frequency and a modulated pump beam is used to periodically heat the surface of a semiconductor wafer at a location, thereby generating a disturbance at such location. Two probe beams are provided which are coherent with each other having different frequencies or phase. One probe beam is directed towards the location where the disturbance is generated and the other probe beam is directed towards the sample surface at a location away from the disturbance so that it is substantially unaffected by the disturbance but is subject to substantially the same environmental factors as the location where the disturbance is generated. Reflections of the two probe beams are combined and interfere at a detector, The detector output is analyzed to provide the normalized amplitude of the sidebands for determining the physical characteristics or composition of the wafer, including the dose of any ion implants.

Abstract: A method (1) creates charge carriers in a concentration that changes in a periodic manner (also called “modulation”) only with respect to time, and (2) determines the number of charge carriers created in the carrier creation region by measuring an interference signal obtained by interference between a reference beam and a portion of a probe beam that is reflected by charge carriers at various depths of the semiconductor material, and comparing the measurement with corresponding values obtained by simulation (e.g. in graphs of such measurements for different junction depths). Various properties of the reflected portion of the probe beam (such as power and phase) are functions of the depth at which the reflection occurs, and can be measured to determine the depth of the junction, and the profile of active dopants.

Abstract: A dynamic change detecting apparatus permits selection of a combination condition of various detection sensitivities and dynamic ranges.

Abstract: A method (1) creates charge carriers in a concentration that changes in a periodic manner (also called “modulation”) only with respect to time, and (2) determines the number of charge carriers created in the carrier creation region by measuring an interference signal obtained by interference between a reference beam and a portion of a probe beam that is reflected by charge carriers at various depths of the semiconductor material, and comparing the measurement with corresponding values obtained by simulation (e.g. in graphs of such measurements for different junction depths). Various properties of the reflected portion of the probe beam (such as power and phase) are functions of the depth at which the reflection occurs, and can be measured to determine the depth of the junction, and the profile of active dopants.

Abstract: A method for the determination of grain orientation in a film sample is provided comprising the steps of measuring a first transient optical response of the film and determining the contribution to the transient optical response arising from a change in the energy distribution of the electrons in the sample, determining the contribution to the transient optical response arising from a propagating strain pulse within the sample, and determining the contribution to the transient optical response arising from a change in sample temperature of the sample. The grain orientation of the sample may be determined using the contributions to the transient optical response arising from the change in the energy distribution of the electrons, the propagating strain pulse, and the change in sample temperature. Additionally, a method for determination of the thickness of a film sample is provided. The grain orientation of the sample is first determined.

Abstract: Faults, dimensions and other characteristics of a material or structure are sensed by a coherent beam's reflection from the material during ultrasonic or very fast vibration. The reflected beam acquires a phase substantially different from its original phase and from the phase of a reference beam split from the common source beam. The reflected beam and the reference beam are superimposed by diffraction in a photorefractive polymer composite adaptive holographic beamsplitter, and the superimposed beams are detected by a photodetector capable of detecting small interference changes from ultrasonic surface displacements or perturbations. An apparatus and method defining an improved homodyne interferometer for performing the method is described.

Abstract: A nondestructive bond testing system is implemented using a pulse laser that sends a single or multiple pulse(s) of controlled magnitude and bombards an object of interest causing a thermoelastic excitation response. This excitation in turn induces an ultrasonic propagation along or through the surface material. By detecting, capturing and interpreting these thermoelastic propagation signatures, the attachment condition of the joining materials is determined. The technique is a significant improvement over traditional mechanical pull, shear or contact type techniques. The techniques are implemented in automated high speed inspection systems suitable for real time manufacturing application. Particular applications include evaluating material joining in microelectronics manufacture (such as ball bonds) and thin coating processes.

Abstract: A modulated LIDAR system is disclosed, in which a laser for generating an tical carrier signal and a microwave generator for generating a coded microwave signal are provided. A modulator is further provided for modulating the carrier signal with the microwave signal, whereby a modulated signal is generated. A method of detecting a reflective surface is also disclosed, in which an optical carrier signal is generated, the carrier signal is modulated with a coded microwave signal, the modulated signal is reflected off of a reflective surface and the reflected signal is recovered.

Abstract: A "laser tape measure" for measuring distance which includes a transmitter such as a laser diode which transmits a sequence of electromagnetic pulses in response to a transmit timing signal. A receiver samples reflections from objects within the field of the sequence of visible electromagnetic pulses with controlled timing, in response to a receive timing signal. The receiver generates a sample signal in response to the samples which indicates distance to the object causing the reflections. The timing circuit supplies the transmit timing signal to the transmitter and supplies the receive timing signal to the receiver. The receive timing signal causes the receiver to sample the reflection such that the time between transmission of pulses in the sequence in sampling by the receiver sweeps over a range of delays.