Nanostructured Optical Elements for Faster 5D Data Writing
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Solution Overview
Problem
The challenge of implementing precise and high-speed data writing in 5D optical data storage is hindered by the difficulty in simultaneously positioning multiple laser pulses accurately at each voxel location to create anisotropic nanopores with homogeneous birefringence.
Innovation Solution
A two-stage method involving circularly polarized femtosecond laser pulses to create spherical nanopores followed by non-circularly polarized pulses to transform them into oblate spheroidal nanopores, enabling faster data writing by reducing the need for precise spatial alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple laser pulses are applied to each voxel position to create homogeneous birefringence, then the quality of the nanopores is improved, but the data writing speed deteriorates
Solution Approach 1:
The patent applies preliminary action by first creating spherical nanopores using circularly polarized laser pulses before transforming them into oblate spheroidal nanopores. This two-stage approach allows the initial spherical structures to be formed quickly, then selectively transformed in a second stage to achieve the desired birefringence properties, thereby improving overall writing speed while maintaining quality
Solution Approach 2:
The patent utilizes parameter changes by switching between different laser pulse polarizations (circular to linear/elliptical) and adjusting pulse parameters to transform the nanopore shape from spherical to oblate spheroidal. This enables control over the birefringence properties while maintaining high writing speeds through optimized pulse sequences
2Productivity
If the scanning speed of the laser beam is increased to improve data writing speed, then productivity is improved, but the positioning precision of multiple pulses deteriorates
Solution Approach 1:
The patent applies preliminary action by first creating spherical nanopores that are less sensitive to positioning precision requirements. These preliminary spherical structures can be formed at higher scanning speeds, and then transformed in a second stage to achieve the final birefringent properties, thereby decoupling the speed-precision trade-off
Solution Approach 2:
The patent segments the nanopore creation process into two distinct stages: first creating spherical nanopores with relaxed positioning requirements, then transforming them into oblate spheroidal nanopores. This segmentation allows each stage to be optimized independently, with the first stage prioritizing speed and the second stage achieving precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for faster data writing speeds by creating birefringent nanopores with controlled retardance and slow axis orientation using a single pulse or a small number of pulses, enhancing the efficiency of 5D optical data storage.
Implementation Method 1
applying a plurality of circularly polarised focused femtosecond laser pulses to a volume within the substrate to create substantially spherical nanopores in the volume
Implementation Method 2
applying at least one and not more than ten non-circularly polarised focused femtosecond laser pulses to the volume to transform the spherical nanopores into oblate spheroidal nanopores
Implementation Method 3
The individual nanopores have an anisotropic shape that gives a nanostructure comprising the nanopores an overall birefringence with an optical retardance value and slow axis of birefringence
Data Source
AI summary
A method of fabricating an optical element comprises: providing a substrate of a transparent material; applying a plurality of circularly polarised focused femtosecond laser pulses to a volume within the substrate to create substantially spherical nanopores in the volume; and applying at least one and not more than ten non-circularly polarised focused femtosecond laser pulses to the volume to transform the spherical nanopores into oblate spheroidal nanopores.