Such devices are called laser interferometers. Very small displacements can be detected, and larger distances can be measured with precision. With lasers, these measurements can be carried out over extremely long distances. Laser interferometers are used to monitor small displacements in the Earth's crust across geological faults. In manufacturing, such devices are employed to gauge fine wires, to monitor the products of automated machine tools, and to test optical components.
Lasers can be so monochromatic that a small shift in the light frequency can be detected.
For a receding object, the frequency is lowered. The light from many lasers is relatively powerful and can be focused by a conventional lens system to a small spot of great intensity. Thus even a moderately small pulsed laser can vaporize a small amount of any substance and drill narrow holes in the hardest materials. Ruby lasers, for example, are used to drill holes in diamonds for wire drawing dies and in sapphires for watch bearings. For biological research, a finely focused laser can vaporize parts of a single cell, thus permitting microsurgery of chromosomes.