Optical gratings fabricated using the capillary-assisted self-assembly of nanoparticles on a flexible substrate

We demonstrate a cost-effective and high-throughput fabrication technique to deposit colloidal nanoparticles on a patterned polymer substrate using a capillary-assisted self-assembly method over a large area. In particular, we fabricate optical gratings using gold nanoparticles and a polymer substrate. We show the versatility of the technique over different nanoparticle diameters and grating periodicities. Through both experiments and simulations, we show enhanced transmission in the first-order diffraction of the gold-polymer grating as compared to the air-polymer grating. Our fabrication technique also enables the transfer of the nanoparticle pattern from the polymer substrate to any desired surface. Here, we demonstrate the transfer of the nanoparticle grating structure to the tip of optical fibers.

The deposition of nanoparticles on the patterned substrate is mainly dependent on the following parameters: Surface chemistry, Concentration of nanoparticle suspension, Temperature and humidity, and Speed of the blade movement.

With these optimized parameters, we perform deposition of gold nanoparticles on the patterned substrates.

For each periodicity of 720 nm and 1500 nm, we show deposition with nanoparticles of diameters 40, 60, and 80 nm. The details can be found in the journal publication https://doi.org/10.1364/AO.492232.