Lasers are widely used
in metrology due to its unique high degree of monochromaticity. High
monochromaticity yields clear interference fringes. Low power He-Ne laser is preferred in
metrological applications. In metrology, lasers are used in interferometry,
holography and in scanning. Interferometry is a method used for the
determination of distance by the proper measurement of wavelengths. Lasers are
also used for machine tool calibration and alignment testing. This method yields high accuracy and greater
speeds. In a laser scanner, the object is mounted in a space between the laser
source and a receiver. The receiver which contains a photo diode and a
microprocessor computes dimension based on the shadow. Holography is a method
based on interference and requires highly monochromatic light sources. Lasers
are the automatic choice here. Holographic technique is widely used by
automotive industry for the study of noise and vibration.
