US 12,406,695 B1 · Differential phase voxel symbol determination

Abstract

A differential voxel symbol reader is alternatively configured to detect phase or polarization changes in a probe light beam caused by interactions with voxels distributed in an optical storage medium as light-scattering nanostructures. Rather than determine an absolute change in the state of the probe signal from an interaction with a voxel being read, a relative change is detected by comparing the probe light beam against an orthogonally-polarized reference light beam that propagates over an overlapping path with the probe light beam. The overlapping paths for the probe and reference light beams provide that each is subject to substantially the same impairments during propagation through the medium. The overlap largely cancels the effects of light scattering and impairments from the other voxels in the medium that cause shifts in phase and/or polarization which would otherwise scramble the signals to thereby reduce the accuracy and reliability of the reading process.

Claims20

Dependent claims

A method for optically reading data, the method comprising:

providing an optical storage medium having a plurality of voxels located therein, the voxels storing a plurality of corresponding symbols for digitally encoding data, in which the optical storage medium comprises a three-dimensional transparent volume through which light is transmissible from an entrance of the volume to an exit of the volume, and in which a voxel is a light-scattering element in the volume;
focusing a probe light beam at a first point within the volume, the probe light beam propagating in the volume from entrance to exit along a probe light beam propagation path, and in which the probe light beam has a first polarization state at the entrance to the volume;
focusing a reference light beam at a second point within the volume, the reference light beam propagating in the volume from entrance to exit along a reference light beam propagation path, and in which the reference light beam has a second polarization state at the entrance of the volume that is orthogonal to the first polarization state, and wherein the probe and reference light beams propagation paths are at least partly spatially overlapping within the volume;
and
receiving, at an optical reader, the probe and reference light beams at the exit from the volume, the optical reader producing a first intensity signal containing contributions from both the probe and reference light beams.

2 more elements

One or more hardware-based non-transitory computer-readable memory devices storing computer-executable instructions which, upon execution by one or more processors disposed in a computing device, cause the computing device to:

generate a probe light beam that is sequentially focused on a respective sequence of locations within an optical storage medium containing a plurality of voxels arranged in a spatial array, in which each voxel in the plurality provides a respective symbol encoding information for a bitstream;
generate a reference light beam that is sequentially focused on a respective sequence of locations within the optical storage medium, in which a waist of the probe light beam and a waist of the reference light beam are simultaneously focused on different locations within the optical storage medium, and in which the probe light beam and reference light beam at least partially overlap within the optical storage medium;
receive a stream of differentially-encoded symbols produced by interactions of the probe light beam with the plurality of voxels, in which one or more properties of the probe light beam are modifiable through the interactions;
and
compare the probe light beam to the reference light beam to read values of the symbols provided by the plurality of voxels to reproduce the bitstream.

2 more elements

A differential phase voxel reader configured for reading data from an optical storage medium containing a plurality of voxels, comprising:

a polarization beam splitter configured to receive a probe light beam and a reference light beam after propagating through the optical storage medium, wherein the probe light beam and reference light beam are orthogonally polarized and are each simultaneously focused at different locations within the optical storage medium with at least partially overlapping propagation paths through the optical storage medium, and wherein the polarization beam splitter provides a first output and a second output having orthogonal polarization states in which each of the first output and second output have substantially equal contribution from the probe and reference light beams;
a first photodetector arranged to receive the first output of the polarization beam splitter and responsively generate a first electrical signal;
a second photodetector arranged to receive the second output of the polarization beam splitter and responsively generate a second electrical signal;
and
a first differential amplifier arranged to receive the first and second electrical signals and responsively generate a first difference signal indicating a phase difference between the probe light beam and the reference light beam.

2 more elements

Dependencies are inferred from the claim text.

Differential phase voxel symbol determination

Life of this patent

Differential phase voxel symbol determination

Life of this patent

Abstract

Claims20