Transducer for measuring and controlling laser beam wavelengths - uses prism through which beam can be directed at slightly different angles

摘要

The transducer is designed for producing a voltage output dependant on the wavelength of the light in a laser beam, for use in controlling the wavelengths produced by a laser, partic. for certain dyestuff a applications. A laser beam (1) is divided into two separate beams (7, 11) by a half silvered mirror (3) the position of which is adjustable. One half beam is fed via a mirror (8) and filter (9) to a photo multiplier (10) and the output of this can be used to hold the laser output intensity constant. The other half beam is fed through a spectrum separating prism and lens array (2) and thence via a filter (5) to a photosensitive plate (6). Together with the position of the first mirror (3), the output of this represents the wavelength of the laser beam.