Mode Converter Coupling Light to Plasmonic Transducer

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Solution Overview

Problem

Current heat-assisted magnetic recording (HAMR) technologies face limitations in areal data density due to superparamagnetic effects, which hinder reliable data storage, as conventional hard drive media struggle to maintain magnetic orientation changes induced by thermal fluctuations.

Innovation Solution

A mode converter is used to couple light from a fundamental transverse electric (TE) mode to a higher-order TE mode, which is then directed to a plasmonic transducer to generate surface plasmons that heat a recording medium, allowing for localized magnetic orientation changes and improved data storage reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional hard drive media is used to increase areal data density, then storage capacity improves, but superparamagnetic effects cause thermal fluctuations that randomly change magnetic orientations, reducing data reliability

Engineering Contradiction:

Improveareal data densityVSAvoidmagnetic orientation stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the temperature parameter of the magnetic medium by using a plasmonic transducer to locally heat the medium above its Curie temperature, temporarily reducing magnetic coercivity to enable writing, then cooling it to stabilize the magnetic state for reliable storage

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system employs periodic thermal cycling of the magnetic medium - heating above Curie temperature for writing operations, then cooling below for stable storage - allowing repeated write cycles while maintaining data reliability

Inventive Principle:

Principle #19Periodic action

2Use of energy by moving object

If light is coupled at fundamental TE mode to the plasmonic transducer, then coupling efficiency is maintained, but the plasmonic transducer cannot effectively generate surface plasmons, reducing heating efficiency

Engineering Contradiction:

Improvelight coupling efficiencyVSAvoidsurface plasmon generation efficiency

Core Design Contradiction:

Use of energy by moving objectVSPower

Solution Approach 1:

The patent introduces a mode converter as an intermediary component between the waveguide and plasmonic transducer, transforming the light mode from fundamental TE to higher-order TE to enable effective surface plasmon generation while maintaining overall system efficiency

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the optical mode parameter of the light propagating through the waveguide from fundamental TE mode to higher-order TE mode using a mode converter, enabling the plasmonic transducer to effectively generate surface plasmons and heat the magnetic medium

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a large region of the magnetic medium is heated, then magnetic orientation can be changed, but the heated region is too large for high-density data storage

Engineering Contradiction:

Improvemagnetic orientation changeVSAvoidheated region size

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent applies local quality by concentrating the heating effect to a small, localized region on the magnetic medium surface using the plasmonic transducer, enabling precise writing of individual data bits while maintaining high areal data density

Inventive Principle:

Principle #3Local quality

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 solution enhances data storage density by effectively heating a small region of the recording medium above its Curie temperature, maintaining magnetic state and improving data retrieval reliability.

Implementation Method 1

A plasmonic transducer receives the light at the higher order TE mode and generates surface plasmons that heat a recording medium

Methodology Applied

Scientific EffectSurface plasmon generation: Plasma

Implementation Method 2

The surface plasmons are directed via the plasmonic transducer to heat a region on the recording medium

Methodology Applied

Scientific EffectThermal heating: Heating

Implementation Method 3

a small portion, or 'hot spot,' of the magnetic medium is locally heated to its Curie temperature, thereby allowing magnetic orientation of the medium to be changed

Methodology Applied

Scientific EffectCurie temperature effect: Curie Point (ferromagnetic)

Implementation Method 4

a waveguide configured to couple light from a light source at a fundamental transverse electric (TE) mode

Methodology Applied

Scientific EffectWaveguide propagation: Waveguide (optics)

Data Source

PatentUS9251819B2Mode converter coupling energy at a high-order transverse electric mode to a plasmonic transducer

Publication Date: 2016.02.02 SEAGATE TECH LLC

AI summary

A waveguide is configured to couple light from a light source at a fundamental transverse electric (TE) mode. A mode converter outputs the light to an output region of the waveguide at a higher-order TE mode. A plasmonic transducer receives the light at the higher order TE mode and generates surface plasmons that heat a recording medium. The plasmonic transducer includes: an input end proximate the output region of the waveguide and comprising a first convex curved edge; an output end proximate a surface that faces the recording medium, the output end comprising a second convex curved edge and a peg; and linear edges between the first and second convex curved edges.