During the past decades, breakthroughs in nanophotonics and nanofabrication technologies have vigorously promoted the development of optical metastructures. With the help of precise design on metastructures, incident light can be effectively manipulated. However, the difficulty in finding high-index and low-loss dielectrics in visible range limits the application of all-dielectric metastructures for visible wavelengths. Besides, the edge and surface roughness of fabricated metastructure also have more significant effects on its performance.
Here, we report the design of high contrast all-dielectric metastructure for visible range applications using the switchable all-dielectric metastructure an example. The physics behind the high contrast all dielectric metastructure is studied and analyzed. Based on this, the effect of edge and surface roughness on fabricated high contrast all-dielectric metastructure is explained. A method that can optimize the metastructure performance effectively is also proposed.
We present a technology to fabricate large-area gapped plasmonic structures deterministically with atomic precision, high throughput and high reliability at low cost. The technology is based on collapsible nano-fingers fabricated using nanoimprint lithography and ALD. A pair of metallic nanoparticles is placed on top of two nano-fingers in flexible polymer with high aspect ratio. ALD is then used to coat a thin conformal dielectric layer. By collapsing the pair of nano-fingers, two metallic nanoparticles with dielectric coating contact each other. Therefore, the gap size between two metallic nanoparticles is well defined by twice the thickness of the ALD-coated dielectric layers.
As metallic nanoparticles are known to dramatically modify the spontaneous emission of nearby fluorescent molecules and materials, here we examine the role of the gap plasmon resonance on the molecular fluorescence enhancement. Considering quenching effect, the distance between fluorescent molecules and gold nanoparticles should not be too small in order to obtain strongest enhancement. In that sense, to fully exploit plasmonic enhancement on the fluorescent molecules, an appropriate gap size should be kept between the molecule and each metallic nanoparticle, which separates molecules away from the metal to avoid quenching effect. The ALD-defined gap plasmonic nano-finger structure facilitate direct and precise control on the gap size between the molecule and metallic nanoparticle by simply changing ALD film thickness that has atomic precision. This makes collapsible nano-fingers the ideal structure for the optimization of molecular fluorescence enhancement. With the optimally engineered collapsible nano-fingers plasmonic structure, field enhancement and fluorescence quenching at hot spots can be studied in detail, which paves the way for optimal design on strongest plasmonic enhancement of molecular fluorescence.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.