SYSTEMS, DEVICES, AND METHODS FOR SIDE LOBE CONTROL IN HOLOGRAMS
Systems, devices, and methods for side lobe control in holograms are described. The magnitude of the side lobes of a hologram depends on the distribution of refractive index modulation (Δn), therefore control of side lobe magnitude may be achieved by controlling the distribution of Δn. The distribution of Δn may be controlled by replicating a hologram from a master with two reference beams, where the wavelength and angle of each reference beam, the playback angle of the master hologram, and the thickness of the master hologram, the copy holographic recording medium (HRM), and the recording substrate are carefully chosen to achieve a pattern of meta-interference within the HRM that matches the desired distribution of Δn.
1 . A method of producing a hologram with controlled side lobes, the method comprising:
providing a recording substrate comprising a first surface and a second surface opposite the first surface;
mounting a master hologram on the first surface of the recording substrate;
mounting a holographic recording material (“HRM”) on the second surface of the recording substrate;
replicating the master hologram within the HRM with at least two reference beams to produce a hologram with controlled side lobes, wherein the hologram with controlled side lobes comprises a first surface and a second surface opposite the first surface; and
dismounting the hologram with controlled side lobes from the recording substrate.
2 . The method of claim 1 wherein replicating the master hologram within the HRM with at least two reference beams to produce a hologram with controlled side lobes includes replicating the master hologram within the HRM with at least two reference beams to produce a hologram wherein the intensity of each of the side lobes is less than one percent of the intensity of the primary hologram peak.
3 . The method of claim 1 wherein replicating the master hologram within the HRM with at least two reference beams to produce a hologram with controlled side lobes includes replicating the master hologram within the HRM with at least two reference beams to produce a hologram wherein the intensity of at least one of the side lobes is greater than the intensity of the primary hologram peak.
4 . The method of claim 1 , further comprising bleaching the hologram with controlled side lobes.
5 . The method of claim 1 further comprising recording a master hologram.
6 . The method of claim 1 wherein replicating the master hologram within the HRM with at least two reference beams to produce a hologram with controlled side lobes includes replicating the master hologram with at least two reference beams wherein each reference beam is of a different angle than each other reference beam.
7 . The method of claim 1 wherein replicating the master hologram within the HRM with at least two reference beams to produce a hologram with controlled side lobes includes replicating the master hologram with at least two reference beams wherein each reference beam is of a different wavelength than each other reference beam.
8 . The method of claim 1 wherein replicating the master hologram within the HRM with at least two reference beams to produce a hologram with controlled side lobes includes replicating a wavelength-multiplexed master hologram with at least two reference beams to produce a wavelength-multiplexed hologram with controlled side lobes.
9 . The method of claim 8 wherein the wavelength multiplexed hologram with controlled side lobes comprises a blue hologram, a red hologram, and a green hologram, and wherein replicating a wavelength-multiplexed master hologram with at least two reference beams to produce a wavelength-multiplexed hologram with controlled side lobes includes replicating a wavelength-multiplexed master hologram comprising a blue master hologram, a red master hologram, and a green master hologram.
10 . The method of claim 9 wherein replicating a wavelength-multiplexed master hologram comprising a blue master hologram, a red master hologram, and a green master hologram includes replicating a wavelength-multiplexed master hologram comprising a blue master hologram, a red master hologram, and a green master hologram wherein the bandwidth of the red master hologram is greater than the bandwidth of the green master hologram, and wherein the bandwidth of the green master hologram is greater than the bandwidth of the blue master hologram.
11 . The method of claim 8 wherein replicating a wavelength-multiplexed master hologram includes replicating a wavelength-multiplexed master hologram with at least two blue beams of laser light, at least two green beams of laser light, and at least two red beams of laser light.
12 . The method of claim 11 wherein replicating a wavelength-multiplexed master hologram with at least two blue beams of laser light, at least two green beams of laser light, and at least two red beams of laser light includes:
replicating the wavelength-multiplexed master hologram with two blue beams of laser light wherein the two blue beams of laser light differ in wavelength by a first Δλ;
replicating the wavelength-multiplexed master hologram with two green beams of laser light wherein the two green beams of laser light differ in wavelength by a second Δλ; and
replicating the wavelength-multiplexed master hologram with two red beams of laser light wherein the two red beams of laser light differ in wavelength by a third Δλ;
wherein the first Δλ is less than the second Δλ and the second Δλ is less than the third Δλ.
13 . The method of claim 1 wherein replicating the master hologram within the HRM with at least two reference beams to produce a hologram with controlled side lobes includes replicating the master hologram with at least two reference beams to record an initial set of fringes and at least one additional set of fringes within the HRM, wherein the initial set of fringes possesses a phase within the HRM, each additional set of fringes possesses a net phase shift relative to the initial set of fringes within the HRM, and wherein the initial set of fringes and each additional set of fringes meta-interfere.
14 . The method of claim 13 wherein replicating the master hologram with at least two reference beams to record an initial set of fringes and at least one additional set of fringes within the HRM includes replicating the master hologram with at least two reference beams to record an initial set of fringes and at least one additional set of fringes within the HRM wherein:
the initial set of fringes and each additional set of fringes meta-interfere most destructively at a depth within the hologram corresponding to at least one of: the first surface and the second surface; and
the initial set of fringes and each additional set of fringes meta-interfere most constructively at a depth between the first surface and the second surface.
15 . The method of claim 13 wherein replicating the master hologram with at least two reference beams to record an initial set of fringes and at least one additional set of fringes within the HRM includes replicating the master hologram with at least two reference beams to record an initial set of fringes and at least one additional set of fringes within the HRM wherein:
the initial set of fringes and each additional set of fringes meta-interfere most constructively at a depth within the hologram corresponding to at least one of: the first surface and the second surface; and
the initial set of fringes and each additional set of fringes meta-interfere most destructively at a depth between the first surface and the second surface.
16 . The method of claim 1 wherein the master hologram possesses a Bragg peak wavelength, each reference beam possesses a reference beam wavelength, and wherein replicating the master hologram within the HRM with at least two reference beams to produce a hologram with controlled side lobes includes replicating the master hologram within the HRM with at least two reference beams to produce a hologram with controlled side lobes wherein the difference between the Bragg peak wavelength of the master hologram and reference beam wavelength of each reference beam is less than 2 nanometers.
17 . The method of claim 1 wherein replicating the master hologram within the HRM with at least two reference beams to produce a hologram with controlled side lobes includes replicating the master hologram within the HRM with at least two reference beams to produce a hologram with controlled side lobes wherein at least one of the reference beams comprises a plane wave.
18 . The method of claim 1 wherein replicating the master hologram within the HRM with at least two reference beams to produce a hologram with controlled side lobes includes replicating the master hologram within the HRM with at least two reference beams to produce a hologram with controlled side lobes wherein at least one of the reference beams comprises a spherical wave.