Phase modulation method and phase modulating device

A phase modulation apparatus comprising:

• a light source configured to output readout light of which an intensity distribution in an arbitrary section including an optical axis is axially symmetric with respect to the optical axis;
• a spatial light modulator comprising a phase modulation plane including a plurality of two-dimensionally arrayed regions, and configured to modulate the readout light in phase in each of the plurality of regions to generate modulated light;
• and
• a phase distribution computation unit configured to calculate 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, wherein
• the phase distribution computation unit calculates the phase distribution to be displayed on the phase modulation plane by dividing a region on the phase modulation plane which the readout light enters into N (N is an integer of 2 or more) concentric regions A1 . . . AN centered on an optical axis of the readout light and setting sizes of the regions A1 . . . AN such that integration values of an intensity distribution in the regions A1 . . . AN in a section including the optical axis of the readout light are equal to each other, dividing a region on the target plane into N concentric regions B1 . . . BN centered on an optical axis of the modulated light and setting sizes of the regions B1 . . . BN such that integration values of an intensity distribution in the regions B1 . . . BN in a section including the optical axis of the modulated light are equal to each other, obtaining an optical path length Ln from the region An to the region Bn (n is each integer from 1 to N), and determining a phase of the region An based on the optical path length Ln.

A phase modulation apparatus comprising:

• a light source configured to output readout light of which an intensity distribution in an arbitrary section including an optical axis is axially symmetric with respect to the optical axis;
• a spatial light modulator comprising a phase modulation plane including a plurality of two-dimensionally arrayed regions, and configured to modulate the readout light in phase in each of the plurality of regions to generate modulated light;
• and
• a control section configured to control 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, wherein
• the control section comprises a storage configured to store the phase distribution, and
• the phase distribution is calculated by dividing a region on the phase modulation plane which the readout light enters into N (N is an integer of 2 or more) concentric regions A1 . . . AN centered on an optical axis of the readout light and setting sizes of the regions A1 . . . AN such that integration values of an intensity distribution in the regions A1 . . . AN in a section including the optical axis of the readout light are equal to each other, dividing a region on the target plane into N concentric regions B1 . . . BN centered on an optical axis of the modulated light and setting sizes of the regions B1 . . . BN such that integration values of an intensity distribution in the regions B1 . . . BN in a section including the optical axis of the modulated light are equal to each other, obtaining an optical path length Ln from the region An to the region Bn (n is each integer from 1 to N), and determining a phase of the region An based on the optical path length Ln.

A phase modulation method for modulating readout light in phase in each of the plurality of regions to generate modulated light, using a spatial light modulator comprising a phase modulation plane including a plurality of two-dimensionally arrayed regions, 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 first step of dividing a region on the phase modulation plane which the readout light enters into M (M is an integer of 2 or more) regions S1 . . . SM such that integration values of an intensity distribution in the respective regions are equal to each other, and dividing a region on the target plane which the modulated light enters into M regions R1 . . . RM such that integration values of an intensity distribution in the respective regions are equal to each other;
• and
• a second step of calculating the phase distribution by obtaining an optical path length LBm from the region Sm to the region Rm (m is each integer from 1 to M), and determining a phase of the region Sm based on the optical path length LBm.

A phase modulation apparatus comprising:

• a light source configured to output readout light;
• a spatial light modulator comprising a phase modulation plane including a plurality of two-dimensionally arrayed regions, and configured to modulate the readout light in phase in each of the plurality of regions to generate modulated light;
• and
• a phase distribution computation unit configured to calculate 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, wherein
• the phase distribution computation unit calculates the phase distribution to be displayed on the phase modulation plane by dividing a region on the phase modulation plane which the readout light enters into M (M is an integer of 2 or more) regions S1 . . . SM such that integration values of an intensity distribution in the respective regions are equal to each other, dividing a region on the target plane which the modulated light enters into M regions R1 . . . RM such that integration values of an intensity distribution in the respective regions are equal to each other, obtaining an optical path length LBm from the region Sm to the region Rm (m is each integer from 1 to M), and determining a phase of the region Sm based on the optical path length LBm.

A phase modulation apparatus comprising:

• a light source configured to output readout light;
• a spatial light modulator comprising a phase modulation plane including a plurality of two-dimensionally arrayed regions, and configured to modulate the readout light in phase in each of the plurality of regions to generate modulated light;
• and
• a control section configured to control 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, wherein
• the control section comprises a storage configured to store the phase distribution, and
• the phase distribution is calculated by dividing a region on the phase modulation plane which the readout light enters into M (M is an integer of 2 or more) regions S1 . . . SM such that integration values of an intensity distribution in the respective regions are equal to each other, dividing a region on the target plane which the modulated light enters into M regions R1 . . . RM such that integration values of an intensity distribution in the respective regions are equal to each other, obtaining an optical path length LBm from the region Sm to the region Rm (m is each integer from 1 to M), and determining a phase of the region Sm based on the optical path length LBm.