Surface Plasmon Resonant Optical System for TAMR Head
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Solution Overview
Problem
In thermally-assisted magnetic recording, existing optical systems face challenges in achieving high light use efficiency while minimizing the absorption of surface plasmons by the plasmon generator, which can lead to overheating and reduced recording density due to the need for longer plasmon generators that absorb more surface plasmons and increase thermal fluctuations.
Innovation Solution
A surface plasmon resonating optical system is implemented, featuring a waveguide, a plasmon generator coupled in a surface plasmon mode, and a resonator mirror to amplify excited surface plasmons, reducing the length of the plasmon generator and preventing overheating, thereby enhancing light use efficiency and generating near-field light with higher intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the plasmon generator is made longer to increase light use efficiency, then the coupling between waveguide light and plasmon generator is strengthened, but the absorption of surface plasmons by the plasmon generator increases causing overheating
Solution Approach 1:
The optical system is segmented into distinct functional components: a waveguide for light transmission, a plasmon generator for surface plasmon excitation, and a separate resonator structure for plasmon amplification. This segmentation allows the plasmon generator to be kept short (reducing absorption and overheating) while the resonator provides the necessary amplification function separately.
Solution Approach 2:
A resonator structure is introduced as an intermediary element between the plasmon generator and the magnetic recording medium. This resonator acts as a mediator that amplifies the surface plasmons generated by the short plasmon generator, enabling sufficient NF-light intensity without requiring a long plasmon generator that would cause overheating.
2Temperature
If the plasmon generator is made shorter to reduce absorption and overheating, then the temperature rise is reduced, but the light use efficiency decreases due to weaker coupling
Solution Approach 1:
The system merges the functions of light coupling and plasmon amplification into a unified optical system. The waveguide couples light to the short plasmon generator, and the integrated resonator structure amplifies the generated surface plasmons, achieving both efficient energy use and temperature control through functional integration.
Solution Approach 2:
The resonator serves as an intermediary that compensates for the reduced coupling efficiency of the short plasmon generator by providing plasmon amplification, thereby maintaining light use efficiency without requiring increased generator length.
3Illumination intensity
If a longer plasmon generator is used to increase NF-light intensity, then more surface plasmons are excited, but thermal fluctuations increase reducing recording density
Solution Approach 1:
The system segments the NF-light generation function into two parts: a short plasmon generator that excites surface plasmons with minimal thermal effects, and a resonator structure that amplifies these plasmons to achieve high NF-light intensity. This segmentation prevents thermal fluctuations from degrading recording density while maintaining sufficient illumination intensity.
Solution Approach 2:
The resonator acts as an intermediary amplification stage that boosts the NF-light intensity from the short plasmon generator without introducing additional thermal effects, thereby achieving high recording density by decoupling intensity generation from thermal generation.
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 system achieves higher light use efficiency and prevents overheating, enabling thermally-assisted magnetic recording with increased recording density by amplifying surface plasmons using a resonator structure, even with a shorter plasmon generator.
Implementation Method 1
a waveguide 35 for transmitting a laser light 53
Implementation Method 2
a plasmon generator 36 which is coupled with the laser light 53 in a surface plasmon mode and excites surface plasmons
Implementation Method 3
a resonator mirror 39 which reflects the surface plasmons excited by the laser light 53 in the plasmon generator 36
Implementation Method 4
generating near-field light from the plasmon generator
Data Source
AI summary
Provided is a surface plasmon resonating optical system emitting near-field light (NF-light) with a higher light density. The system comprises: a waveguide through which a light for exciting surface plasmon propagates; a plasmon generator that couples with the light in a surface plasmon mode and emits NF-light from its NF-light generating end surface; and a resonator mirror that reflects the excited surface plasmon, provided on the side of the plasmon generator opposite to the NF-light generating end surface. In the system, the excited surface plasmon can be amplified by using a resonator structure while reducing the length of the plasmon generator to reduce absorption of surface plasmon and prevent overheating of the plasmon generator.