Refractive index sensing using the metal layer in DVD-R discs

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Grating-based biosensors are crucial for integrated sensing devices.
• Manufacturing high-quality, large-scale, and affordable metal gratings remains a significant challenge.

Purpose of the Study:

• To introduce a simple, low-cost method for fabricating high-quality metal gratings.
• To demonstrate the utility of these gratings in refractive index sensing.

Main Methods:

• Fabrication of metal gratings by peeling the metal layer from a DVD-R disc.
• Characterization of the grating structure using atomic force microscopy (AFM).
• Experimental refractive index sensing using two configurations (wavelength modulation and laser power modulation).

Main Results:

• AFM confirmed a high-quality metal grating with a period of 740 nm and depth of 86 nm.
• Refractive index sensing achieved with a sensitivity of 637 nm/RIU using wavelength modulation.
• Sensitivity is comparable to or exceeds existing grating-coupled sensors.

Conclusions:

• The DVD-R peeling method offers an extremely simple and low-cost approach to produce high-quality metal gratings.
• This method has the potential to significantly reduce the cost of grating fabrication.
• The developed gratings can promote the advancement of grating-based surface plasmon resonance (SPR) sensors.