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Grating couplerWikipedia

The software module of this package consists of a proprietary application that enables quick, easy setting of the digitizer board, real-time view of acquired waveform and storage in an easy-to-access file format.

Flexible optical system for easy beam delivery and beam collection using large core optical fibres with a simple connection to the detection unit.

Tamir, T., Peng, S.T. Analysis and design of grating couplers. Appl. Phys. 14, 235–254 (1977). https://doi.org/10.1007/BF00882729

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Tecnar offers an optional scanning unit for the laser-ultrasonic imaging of small-sized defects. The motorized scanning unit provides two-axis scanning over a range of 100 mm x 100 mm. The scanning unit is mounted on a breadboard and supplied with a support for Tecnar’s laser UT probes.

For background and an extensive bibliography up to early 1975, see T. Tamir (ed.):Integrated Optics, Topics inApplied Physics 7 (Springer, New York, Heidelberg, Berlin 1975), Chap. 3, p. 84

The detection laser records the information from the sample surface motion and carries it to the receiver. It’s important to choose the correct amount of laser output power to ensure it matches the application’s requirements, such as:

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The generation laser is the hammer that generates the ultrasonic probing pulse. The stronger the laser, the better the information.

Tecnar is the world leader in industrial laser ultrasonics for one solid reason: the PDL, our proprietary, high-power, pulsed-detection laser. To this day, the PDL is the only laser of its kind in the world.

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S. T. Peng, T. Tamir: “Effects of groove profile on the performance of dielectric grating couplers”,Proc. Symp. Optical and Acoustical Micro-Electronics, (Polytechnic Press, New York, 1974) p. 377

Based on an accurate perturbation analysis of the guiding properties of dielectric gratings, simple design criteria are developed for grating couplers which transfer the energy of a beam into or out of an optical waveguide. Gratings having arbitrary groove shapes are considered and explicit formulae are given for the leakage parameters of gratings with symmetric profiles. The results cover TEv and TMv modes and they apply to both shallow and deep grating grooves. The variation of the leakage parameter α in rectangular gratings is examined in detail; these rectangular gratings are then used as basic configurations for predicting the characteristics of other grating profiles. Particular attention is given to trapezoidal and triangular profiles and gratings with asymmetric profiles are also discussed.

The PDL is a high-power laser-ultrasonic detection laser unit based on the long-pulsed amplification of a frequency-stabilized Nd:YAG seed laser, specially designed for laser-ultrasonic applications on rough surfaces:

The Marathon™ is a diode-based, high-power, q-switched laser that delivers a fast firing rate with unmatched reliability. This proprietary Tecnar product was specifically designed for use in harsh and difficult environments. Based on diodes rather than flash lamp technology, the Marathon doesn’t require periodic maintenance. From start to finish, the Marathon truly goes the distance for years of trouble-free operation in all kinds of environments.

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The hardware module of this package consists of a PC board digitizer with a sampling rate of 125 Msamples/sec., 14 bits ADC and 60 MHz bandwidth.

The receiver is at the heart of all laser-ultrasonic systems, extracting ultrasonic information from the collected laser light.

T. Tamir, S. T. Peng: “Network methods for integrated optics devices”,Proc. Intern. Conf. Applic. Holography and Optical Data Processing (Pergamon Press, Oxford, 1977)