Near-field light generating element for HAMR head
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing heat-assisted magnetic recording techniques face challenges with excessive temperature rise in near-field light generating parts, such as plasmon antennas, leading to reduced light use efficiency and difficulties in maintaining proper proximity to magnetic poles, which affects the recording density and accuracy.
Innovation Solution
A near-field light generating element comprising a waveguide and a near-field light generating layer that couples light in a surface plasmon mode, avoiding direct irradiation and allowing for efficient light propagation and reduced temperature rise, with a tapered design and refractive index optimization to enhance light use efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a plasmon antenna is used to generate near-field light for heat-assisted magnetic recording, then near-field light can be generated to reduce anisotropic magnetic field, but excessive temperature rise occurs in the plasmon antenna leading to reduced light use efficiency
Solution Approach 1:
The patent introduces a waveguide as an intermediary component between the light source and the magnetic recording medium. The waveguide transmits light to the generating layer, which then produces near-field light through surface plasmon excitation. This intermediary structure distributes and controls the light energy more effectively, preventing excessive concentration of thermal energy in a single location while maintaining the necessary heating effect for magnetic recording.
Solution Approach 2:
The patent employs a tapered structure for the near-field light generating layer, where the thickness gradually changes from the base to the tip. This geometric parameter variation allows for controlled light propagation and surface plasmon excitation along the tapered structure. The changing cross-sectional area optimizes the interaction between light and the generating layer, improving light use efficiency while controlling temperature distribution to prevent excessive heating.
2Manufacturing precision
If the plasmon antenna is made smaller to improve spatial resolution, then recording density increases, but temperature rise becomes more severe due to smaller volume
Solution Approach 1:
The patent transitions from a conventional three-dimensional plasmon antenna structure to a two-dimensional tapered generating layer integrated with a waveguide. This dimensional change allows the light interaction area to be extended along the waveguide while maintaining a small footprint at the recording interface. The tapered geometry provides a gradual transition in cross-sectional area, enabling better heat dissipation across the extended structure while concentrating the near-field light generation at the tip for high spatial resolution.
3Use of energy by moving object
If direct laser irradiation is used on the magnetic recording medium, then heating efficiency is high, but spatial resolution is limited by the light spot size
Solution Approach 1:
The patent segments the light interaction process into two distinct stages: first, light propagates through the waveguide to the generating layer; second, the generating layer converts this light into near-field light through surface plasmon excitation. This segmentation allows the bulk of the light energy to be delivered efficiently through the waveguide (high heating efficiency), while the near-field light generation occurs at a concentrated interface with the magnetic medium (high spatial resolution), decoupling the two conflicting requirements.
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 solution effectively suppresses excessive temperature rise and improves light use efficiency, enabling better heat-assisted magnetic recording with enhanced recording density and accuracy by generating near-field light through surface plasmons, maintaining the magnetic pole proximity and reducing thermal disturbances.
Implementation Method 1
a portion of a side surface of the waveguide being opposed to a portion of the propagation surface of the near-field light generating layer with a predetermined spacing so that the light propagating through the waveguide is coupled with the near-field light generating layer in a surface plasmon mode
Implementation Method 2
a propagation surface on which surface plasmon excited by the light propagates; and a near-field light generating end at which near-field light is generated
Data Source
AI summary
Provided is a near-field light generating element capable of avoiding excessive temperature rise, which comprises a waveguide and a near-field light generating layer. The layer comprises: a propagation surface on which surface plasmon excited by the light propagates; and a near-field light generating end at which near-field light is generated. The end is one end of the propagation surface. And a portion of the side surface of the waveguide is opposed to a portion of the propagation surface of the near-field light generating layer with a predetermined spacing so that the light propagating through the waveguide is coupled with the near-field light generating layer in a surface plasmon mode. The near-field light generating layer is preferably tapered toward the near-field light generating end.