Half Bowtie Aperture Nanoscale Optical Antenna for HAMR
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Solution Overview
Problem
Current heat assisted magnetic recording (HAMR) technologies face challenges in achieving nanoscale spot sizes due to the limitations of conventional far-field optics, which are not suitable for next-generation data storage requiring bit sizes in the tens of nanometers, and there is a need for cost-effective methods to generate small gaps in nanoscale optical antennas for high data density.
Innovation Solution
A half bowtie aperture nanoscale optical antenna is designed and fabricated using a standard lithography method, with a gap size as small as 1 nm, allowing for the production of an optical spot as small as 5-20 nm, enhancing data storage density by focusing light into nanometer-size spots with high intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional far-field optics are used for heating in HAMR, then the system is simple and easy to manufacture, but the spot size is too large (on the order of 400 nm) to achieve next-generation data storage density
Solution Approach 1:
The patent introduces a near-field transducer as an intermediary component between the laser source and the magnetic storage medium. This NFT couples optical energy to surface plasmons, which then concentrate the energy into a nanoscale spot on the medium. The intermediary enables far-field optics to achieve near-field focusing capabilities, resolving the contradiction between simplicity and precision.
Solution Approach 2:
The patent changes the operational parameters by transitioning from far-field to near-field optics. By operating in the near-field regime (within nanometers of the medium surface), the system achieves diffraction-limited spot sizes of tens of nanometers rather than hundreds of nanometers, enabling high-density storage while using standard lithography to fabricate the NFT structure.
2Illumination intensity
If a full bowtie aperture nanoscale optical antenna is fabricated, then the field intensity is enhanced, but the manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent employs a half-bowtie aperture design instead of a symmetric full bowtie. This asymmetric structure maintains the essential field-enhancing functionality by creating a sharp edge that couples efficiently to surface plasmons, while dramatically simplifying fabrication. The half-bowtie can be manufactured using standard lithography techniques, avoiding the complex alignment and fabrication steps required for symmetric bowtie structures.
Solution Approach 2:
The patent extracts only the essential functional element needed for field enhancement - a sharp edge or aperture - from the complete bowtie structure. By removing the redundant symmetric portion, the design retains its plasmonic coupling capability while becoming much easier to manufacture with conventional processes.
3Manufacturing precision
If the gap size in the nanoscale optical antenna is reduced to achieve smaller spot sizes, then data storage density increases, but the difficulty of fabrication increases
Solution Approach 1:
The patent replaces mechanical fabrication methods (such as focused ion beam milling or electron beam lithography) with standard optical lithography. By using photoresist patterns and conventional lithographic processes, the system achieves precise gap size control (tens of nanometers) through chemical and photonic processes rather than direct mechanical manipulation, significantly reducing fabrication difficulty.
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
The half bowtie antenna achieves significantly improved spot sizes and data storage density, overcoming the limitations of conventional antennas by enabling precise fabrication of small gaps, thus facilitating high-density data writing in magnetic storage devices.
Implementation Method 1
Nanoscale optical antennas or NFT are used to focus light to a nanoscale spot beyond the physical diffraction limit of light
Implementation Method 2
using a laser beam to radiate the medium through an optical near field transducer (NFT) and raising the temperature of the medium above the Curie temperature
Implementation Method 3
When illuminated by a laser beam, electric potential and hence currents are induced in the wings (102) of the antenna (100), which flow to the tips (102)
Data Source
AI summary
An antenna for heat assisted magnetic recording is disclosed. The antenna includes an optically opaque material and an optically transparent material positioned on the optically opaque material, the optically transparent material includes a half bowtie shape which includes a first half-wing substantially shaped in form of a right angle trapezoid, having a height substantially equal to the overall height of the half bowtie, a second half-wing substantially shaped in form of a mirror image of the first half-wing and formed proximate and coupled to the first half-wing by a substantially rectangular aperture having an aperture width and an aperture height. The aperture height is as small as 1 nm.