EAMR Head Reflective Grating Optical Coupling
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Solution Overview
Problem
Conventional energy-assisted magnetic recording (EAMR) transducers face challenges in efficiently coupling sufficient energy from a laser to the recording media, affecting their ability to write data effectively.
Innovation Solution
The EAMR transducer is enhanced with a reflective grating that recycles energy reflected from the air-bearing surface, directing it back to the near-field transducer, which is positioned between the waveguide and the grating, allowing for improved optical efficiency and energy coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional waveguide and grating are used to couple light to the NFT, then the structure is simple, but the optical efficiency is insufficient to deliver sufficient power to heat the media
Solution Approach 1:
A reflective grating is introduced as an intermediary component between the waveguide and the NFT. This grating captures light reflected from the air-bearing surface and redirects it into the waveguide, which then guides it to the NFT. This intermediary structure enables additional light paths to reach the NFT, improving optical efficiency without fundamentally changing the core transducer architecture.
Solution Approach 2:
The invention utilizes the reflective grating to exploit the reflected light dimension that would otherwise be lost. By capturing light at a different angular dimension (reflected light) and redirecting it through the waveguide system, the design adds an additional light delivery pathway, effectively using another dimension of light propagation to improve coupling efficiency.
2Power
If more power is delivered to the media, then heating effectiveness improves, but the NFT cannot couple sufficient energy into the media with conventional design
Solution Approach 1:
The reflective grating captures light that would otherwise be discarded (reflected light from the air-bearing surface) and recovers it by redirecting into the waveguide system. This recovered light is then guided to the NFT and ultimately to the media, converting what would be energy loss into useful heating power, thereby improving both power delivery and energy coupling efficiency.
Solution Approach 2:
The system establishes a continuous light delivery mechanism by capturing reflected light and continuously redirecting it through the waveguide to the NFT. This creates an ongoing useful action where light that would otherwise be lost is continuously recovered and utilized, ensuring sustained high power delivery to the media without interruption or energy waste.
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 configuration enhances the optical efficiency and performance of the EAMR transducer by ensuring that more energy is focused onto the recording media, improving data writing capabilities.
Implementation Method 1
A first portion of the energy reflects off of the ABS at a reflected angle. The reflective grating is configured to receive the first portion of the energy at the reflected angle from the ABS and to reflect a second portion of the energy toward the ABS.
Implementation Method 2
The reflective grating is configured to receive the first portion of the energy at the reflected angle from the ABS and to reflect a second portion of the energy toward the ABS.
Implementation Method 3
The NFT 22 focuses the light to magnetic recording media (not shown), such as a disk. In operation, light from the laser is coupled to the conventional EAMR transducer 10 using the grating 20. The waveguide 12 directs light from the grating 12 to the NFT 22. The NFT 22 focuses the light from the waveguide 12 and heats a small region of the conventional media (not shown).
Data Source
AI summary
A method and system provide an EAMR transducer having an air-bearing surface (ABS) that resides near a media during use. The EAMR transducer includes a write pole, coil(s), a near field transducer (NFT), a waveguide, and a reflective grating. The write pole writes to a region of the media. The coil(s) energize the write pole. The NFT is proximate to the ABS and focuses the energy onto the media. The waveguide is configured to direct the energy from the laser toward the NFT at an incident angle with respect to the ABS. A first portion of the energy reflects off of the ABS at a reflected angle. The reflective grating receives the first portion of the energy at the reflected angle from the ABS and reflects a second portion of the energy toward the ABS. The NFT resides between at least part of the waveguide and the reflective grating.