Diffraction efficiency measuring method and diffraction efficiency measurement equipment

摘要

PROBLEM TO BE SOLVED: To shorten the time measuring for the diffraction efficiency not dependent on the aberration with a diffraction optical element such as hologram objective lens for use in an optical head, and make the light spot evaluation of the condensing performance as an optical component. ;SOLUTION: The emitted light from a semiconductor laser 11 is made a parallel light flux by a collimator lens 31 and cast on a hologram element so that a diffraction is generated. A desired diffracted light is condensed by a condenser lens and passed through a microscope 51, and the quantity of diffraction light is measured by a photo-quantity sensing means 41 through utilization of eclipse of unnecessarily diffracted light flux and enlargement of the condensed image of the desired diffracted light. Addition of a light spot observing means will permit accomplishment of a still more precise measurement to be conducted while the condensation spot performance is evaluated.;COPYRIGHT: (C)1997,JPO