| 摘要 |
A method and apparatus for determining the wavelength of a light beam wherein the light beam is directed through a liquid crystal cell functioning as a variable retarder, wherein the voltage applied to the cell is ramped to vary the retardation of the cell between maximum and minimum values, wherein the light from the beam passing through the cell is detected, wherein the intensity of the detected light is monitored, which intensity alternately passes through maximum and minimum values as the retardation of the cell is varied between its maximum and minimum values, and wherein the number of times the intensity alternates between its maximum and minimum values is determined to provide an indication of the wavelength of the light beam.
|
