MEASUREMENTS ON EFFICIENCY OF ECHELETTE GRATINGS
Ohio State University
The efficiency (ratio of the flux diffracted in the best order to the incident flux) has been measured for a number of echelette gratings as a function of the wave number in the visible region. The results are in good agreement with a very simple theory according to which the curve (efficiency versus wave number) is periodical and composed of selections similar to the upper half of the central maximum of the conventional diffraction curve. When properly used all the gratings investigated have efficiency varying as a function of the wave-number, between a maximum value and approximately the half of this maximum value. The case of gratings used far from the Littrow position has been examined, both theoretically and experimentally and it will be proved that this is not infavorable.
Author Institution: Laboratoires de C.N.R.S.