Solid Immersion Lens Meta-material Slabs Heat-assisted Recording

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Solution Overview

Problem

Existing heat-assisted recording devices using optical antennas are inefficient due to energy dissipation and sensitivity to head-media space and fabrication variances, which affect the precision and effectiveness of heat-assisted recording.

Innovation Solution

A solid immersion lens comprising meta-material slabs with alternating layers of different materials and a core with a lower index of refraction, designed to propagate evanescent waves and direct surface plasmons to a focused area, reducing energy loss and fabrication sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an optical antenna is used to focus energy at the storage medium surface, then a tiny confined optical spot can be achieved beyond diffraction limit, but energy dissipation occurs and the device becomes sensitive to head-media space and fabrication variances

Engineering Contradiction:

Improveoptical spot confinement precisionVSAvoidenergy dissipation

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

A solid immersion lens is introduced as an intermediary component between the optical antenna and the storage medium. The lens focuses the optical energy more effectively onto the storage medium while reducing energy dissipation through its refractive properties, thereby resolving the contradiction between achieving a confined optical spot and minimizing energy loss.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The solid immersion lens is constructed from composite materials with specific refractive indices. By using materials with appropriate optical properties, the lens enhances the confinement of optical energy while reducing dissipation, thus improving both spot precision and energy efficiency simultaneously.

Inventive Principle:

Principle #40Composite materials

2Temperature

If an optical antenna is used for heating the storage medium, then heat-assisted recording can be achieved, but the device is sensitive to head-media space and fabrication variances in antenna shape

Engineering Contradiction:

Improvestorage medium heating capabilityVSAvoidsensitivity to head-media space and fabrication variances

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The solid immersion lens serves as an intermediary that compensates for variations in head-media space and antenna fabrication. It provides a more robust focusing mechanism that is less sensitive to these variations, thereby improving the reliability of heat-assisted recording while maintaining the ability to heat the storage medium effectively.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If a solid immersion lens with meta-material slabs is used, then energy focusing is enhanced and fabrication sensitivity is reduced, but the device complexity increases

Engineering Contradiction:

Improveenergy dissipation reductionVSAvoidlens structure complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The solid immersion lens utilizes changes in the refractive index parameter of the materials to achieve enhanced energy focusing. By carefully selecting materials with appropriate refractive indices and designing the lens geometry, the system reduces energy dissipation and fabrication sensitivity while managing the complexity through optimized parameter selection rather than overly complex structures.

Inventive Principle:

Principle #35Parameter changes

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 the focusing of energy onto a recording medium, improving the precision and efficiency of heat-assisted recording by minimizing energy dissipation and variability, resulting in a more effective and reliable recording process.

Implementation Method 1

The meta-material slabs are adapted to propagate an evanescent wave in a direction parallel to an axis to form a cone-shaped wave along the axis

Methodology Applied

Scientific EffectEvanescent wave propagation:

Implementation Method 2

The core directs surface plasmons that are excited by the cone-shaped wave to a focused area coincident with the axis

Methodology Applied

Scientific EffectSurface plasmon excitation and direction:

Implementation Method 3

An optical antenna relies on excitation of local surface plasmon (LSP) at an interface between a metal of free electrons and a dielectric material

Methodology Applied

Scientific EffectLocal surface plasmon excitation:

Implementation Method 4

A portion of the field can tunnel into an adjacent storage medium, which absorbs associated energy, raising the temperature of the adjacent storage medium locally

Methodology Applied

Scientific EffectOptical energy absorption and heating: Absorption (EM radiation)

Data Source

PatentUS7864434B2Solid immersion focusing apparatus for high-density heat assisted recording

Publication Date: 2011.01.04 SEAGATE TECH LLC

AI summary

In a particular embodiment, a solid immersion lens includes meta-material slabs formed from multiple layers of at least two different compositions. Each meta-material slab has a first effective index of refraction. The meta-material slabs are adapted to propagate an evanescent wave in a direction parallel to an axis to form a cone-shaped wave along the axis. The solid immersion lens further includes a core sandwiched between the meta-material slabs along the axis and having a second index of refraction that is less than the first effective index of refraction. The core directs surface plasmons that are excited by the cone-shaped wave to a focused area coincident with the axis.