SYSTEM AND METHOD FOR HOLOGRAPHIC WAVE-FRONT PRINTING

1 . A holographic recording system comprising:

a linear translation stage configured to position a holographic material layer;

a light source configured to emit a laser beam;

a beam splitting subsystem configured to:

split the laser beam into a first light beam and a second light beam; and

direct the second light beam towards the holographic material layer;

a spatial-light modulator configured to implement a fringe pattern that modulates the first light beam to generate an object beam;

a demagnification optical subsystem configured to demagnify the object beam; and

a switchable grating stack configurable to direct the object beam to a set of directions towards the holographic material layer to interfere with the second light beam.

2 . The holographic recording system of claim 1 , wherein the object beam is characterized by a freeform wave-front.

3 . The holographic recording system of claim 1 , wherein the fringe pattern includes a computer-generated hologram.

4 . The holographic recording system of claim 1 , wherein the fringe pattern is configured to modulate at least one of a phase or an amplitude of the first light beam.

5 . The holographic recording system of claim 1 , wherein:

the switchable grating stack includes a plurality of polarization gratings arranged in a stack; and

each polarization grating in the plurality of polarization gratings is configurable to direct a right-handed circularly polarized light beam to a first direction and direct a left-handed circularly polarized light beam to a second direction.

6 . The holographic recording system of claim 5 , wherein the plurality of polarization gratings includes at least one of a right-handed circular polarization grating or a left-handed circular polarization grating.

7 . The holographic recording system of claim 5 , wherein the plurality of polarization gratings includes at least one of a polarization volume grating, a passive Pancharatnam-Berry phase (PBP) grating, or an active PBP grating.

8 . The holographic recording system of claim 5 , wherein each polarization grating in the plurality of polarization gratings is configurable to:

diffract the right-handed circularly polarized light beam to one of ±1 diffraction orders; and

diffract the left-handed circularly polarized light beam to another one of the ±1 diffraction orders.

9 . The holographic recording system of claim 5 , wherein each polarization grating in the plurality of polarization gratings is configured to:

diffract one of the right-handed circularly polarized light beam and the right-handed circularly polarized light beam to one of ±1 diffraction orders; and

maintain a propagation direction of another one of the right-handed circularly polarized light beam and the right-handed circularly polarized light beam.

10 . The holographic recording system of claim 5 , further comprising a plurality of switchable half-wave plates interleaved with the plurality of polarization gratings, wherein each of the plurality of switchable half-wave plates is configured to:

when switched on, convert a right-handed circularly polarized input beam into a left-handed circularly polarized output beam and convert a left-handed circularly polarized input beam into a right-handed circularly polarized beam; and

when switched off by a voltage signal, maintain a polarization state of an input beam.

11 . The holographic recording system of claim 5 , wherein each polarization grating in the plurality of polarization gratings is characterized by a different respective grating period.

12 . The holographic recording system of claim 5 , wherein:

the plurality of polarization gratings includes a plurality of active gratings; and

each active grating in the plurality of active gratings is configured to:

when switched on, diffract a circularly polarized light beam and change a polarization state of the circularly polarized light beam; and

when switched off by a voltage signal, maintain a propagation direction and a polarization state of an incident beam.

13 . The holographic recording system of claim 1 , further comprising:

a lens positioned with respect to the spatial-light modulator such that the spatial-light modulator is at a focal plane of the lens; and

a low-pass filter positioned at another focal plane of the lens and configured to filter the object beam.

14 . The holographic recording system of claim 1 , wherein the demagnification optical subsystem comprises a telecentric subsystem that includes two lenses characterized by different respective focal lengths.

15 . The holographic recording system of claim 1 , wherein the set of directions includes at least a direction characterized by an angle greater than 300 with respect to a surface normal direction of the switchable grating stack.

16 . The holographic recording system of claim 1 , further comprising:

a second spatial-light modulator configured to implement a second fringe pattern that modulates the second light beam; and

a second demagnification optical subsystem configured to demagnify the second light beam and direct the second light beam towards the holographic material layer.

17 . The holographic recording system of claim 16 , further comprising:

a lens positioned with respect to the second spatial-light modulator such that the second spatial-light modulator is at a focal plane of the lens; and

a low-pass filter positioned at another focal plane of the lens and configured to filter the second light beam.

18 . A method of recording of a hologram element of a plurality of hologram elements of a hologram, the method comprising:

controlling a linear translation stage to position a holographic material layer on the linear translation stage to a first position;

providing data for implementing a fringe pattern to a spatial-light modulator, the fringe pattern, when illuminated by a collimated light beam, generating an object beam;

filtering the object beam;

demagnifying the object beam;

configuring a switchable grating stack to steer the object beam to a direction of a set of discrete directions; and

exposing an area of the holographic material layer to the object beam and a reference beam to form the hologram element.

19 . The method of claim 18 , further comprising:

providing data for implementing a second fringe pattern to a second spatial-light modulator, the second fringe pattern, when illuminated by a second collimated light beam, generating the reference beam;

filtering the reference beam; and

demagnifying the reference beam.

20 . The method of claim 18 , wherein:

the switchable grating stack includes a plurality of polarization gratings and a plurality of switchable half-wave plates arranged in a stack; and

each polarization grating in the plurality of polarization gratings is configurable to direct a right-handed circularly polarized light beam to a first direction and direct a left-handed circularly polarized light beam to a second direction.