Near-field light generator with inclined waveguide end surface
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Solution Overview
Problem
In thermally-assisted magnetic recording, the degradation of thermal stability in magnetic microparticles due to reduced volume leads to challenges in maintaining recording density and accuracy, with existing near-field light generators causing thermal expansion and efficiency issues in plasmon antennas, resulting in write errors and noise.
Innovation Solution
A near-field light generator with a waveguide and plasmon antenna design where the waveguide's end surface is inclined to prevent non-transformed light from reaching the plasmon antenna, ensuring efficient coupling and minimizing unwanted heating and noise, using a buffering portion with a lower refractive index to control light propagation and emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser light is directly applied to a plasmon antenna to generate near-field light, then the near-field light generation efficiency is improved, but the temperature of the plasmon antenna rises excessively causing thermal expansion and read head element displacement
Solution Approach 1:
A waveguide is introduced as an intermediary component between the light source and the plasmon antenna. The waveguide couples laser light to the plasmon antenna in a surface plasmon mode, allowing light energy to be transferred without direct application to the antenna. This mediator approach enables efficient near-field light generation while preventing excessive temperature rise in the plasmon antenna, as the waveguide confines and directs the light energy along a controlled path rather than concentrating it directly on the antenna structure.
2Productivity
If the waveguide end surface is perpendicular to the light propagation direction, then the coupling with plasmon antenna is maximized, but non-transformed light is emitted toward the magnetic recording medium causing unwanted writing and noise
Solution Approach 1:
The waveguide end surface is designed with an inclination angle relative to the light propagation direction, breaking the symmetric perpendicular configuration. This asymmetric design causes non-transformed light to be emitted at an angle away from the magnetic recording medium, preventing unwanted writing and noise while maintaining effective coupling with the plasmon antenna. The inclined end surface redirects the light path to a safe direction, separating the useful near-field light generation function from the harmful light emission.
3Productivity
If the distance between the waveguide end and plasmon antenna is reduced to improve coupling, then the near-field light generation efficiency is improved, but light that has not been transformed into surface plasmon reaches the magnetic recording medium causing write errors
Solution Approach 1:
By inclining the waveguide end surface at a specific angle, the design creates asymmetric light emission patterns. Non-transformed light is directed at an angle that prevents it from reaching the magnetic recording medium, even when the waveguide end is positioned close to the plasmon antenna. This geometric arrangement maintains strong coupling efficiency while simultaneously preventing unwanted light-induced writing errors through directional control of residual light emission.
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 design enhances thermal stability, reduces write errors, and maintains high recording density by ensuring precise control over near-field light emission, preventing thermal expansion and noise interference.
Implementation Method 1
laser light propagating through a waveguide is coupled with a plasmon antenna in a surface plasmon mode to cause the excited surface plasmon to propagate to the opposed-to-medium surface
Implementation Method 2
the light that has propagated through the waveguide and is not transformed into surface plasmon is refracted or totally reflected in the inclined end surface of the waveguide
Implementation Method 3
the light that has propagated through the waveguide and is not transformed into surface plasmon is refracted or totally reflected in the inclined end surface of the waveguide
Implementation Method 4
IOUT is the intensity of near-field light emitted from a near-field light generating end of the plasmon antenna after converting the laser light into surface plasmon in the plasmon antenna
Data Source
AI summary
Provided is a near-field light generator capable of avoiding a noise to the generated near-field light. The generator comprises a waveguide and a plasmon antenna comprising a propagation surface or edge, for propagating surface plasmon, extending to a near-field light generating end. A portion of one side surface of the waveguide is opposed to a portion of the propagation surface or edge, so as for the waveguide light to be coupled with the plasmon antenna. And an end surface of the waveguide is inclined in such a way as to become away from the plasmon antenna toward the near-field light generating end side. The light that propagates through the waveguide and is not transformed into surface plasmon is refracted or totally reflected in the inclined end surface, does not come close to the generated near-field light, thus does not become a noise for the generated near-field light.