Patent ID: 9727024
Date: 2017-08-08
CPC Classifications: G02B,G03H

Claim:
1. A phase modulation method, using a spatial light modulator comprising a phase modulation plane including a plurality of two-dimensionally arrayed modulation regions, for modulating readout light, of which a readout light intensity distribution in a first section including a first optical axis of the readout light is axially symmetric with respect to the first optical axis, in phase in each of the plurality of modulation regions to generate modulated light, comprising: a phase distribution calculation step of calculating a phase distribution to be displayed on the phase modulation plane such that the modulated light has a predetermined intensity distribution on a target plane separated by a predetermined optical distance from the phase modulation plane; and a modulated light generation step of displaying the phase distribution on the phase modulation plane, and causing the readout light to enter the phase modulation plane so as to generate the modulated light, wherein the phase distribution calculation step comprises: a step of dividing a light entering region on the phase modulation plane which the readout light enters into N (N is an integer of 2 or more) concentric first regions A setting sizes of the first regions A dividing a target region on the target plane into N concentric second regions B setting sizes of the second regions B a step of calculating the phase distribution by obtaining an optical path length L