ABSTRACT
The first lasers, initially discovered by Maiman at Hughes Research Laboratories in Malibu, California, were pulsed light sources, using optically pumped doped-crystalline rods. They were first reported in Nature in 1960. Because of their initial complexity, rather fragile nature, and need to align mirrors carefully, their first impact was in specialist scientific areas, particularly in spectroscopy and a few areas in metrology. One of the first uses of lasers was in the area of surveying and metrology. In air, at constant temperature and humidity, the collimated beam from a laser provides an excellent "straight line". Even if undesirable thermoclines are present, the beam deflection due to small refractive index gradients is usually not serious for many applications. The types of instruments described earlier have been developed with optical scanning systems, such that they can be projected onto solid objects to measure 3D profiles and even determine finer surface textures.
