A non-resonant, concentrated, narrow beam of light emerging from an illuminated microlens is called a photonic nanojet (PNJ). According to currently prevailing opinion, microspheres and microcylinders are only able to generate a PNJ in their exterior when their refractive index ns (or refractive index contrast) is less than 2. In this Letter we demonstrate that a PNJ can emerge from a microsphere even when ns > 2: first by employing the laws of geometrical optics for a divergent light source; then, by using ray transfer matrix analysis, a mathematical condition for the Gaussian beam (GB) outside the high ns microsphere is derived. The PNJ outside the microsphere with ns = 2.5 is simulated using Generalized Lorenz-Mie theory (GLMT), by using a front focused GB source. The simulated difference between front and back focusing on the dependence of ns is confirmed experimentally by Raman imaging. By opening the PNJ field for high refractive index materials, we believe this work will be a nucleus for new ideas in the field and enable new PNJ applications.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1364/OL.459001 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Fiber optics-based surface enhanced Raman Spectroscopy sensors for rapid multiplex detection of foodborne pathogens in raw poultry.
Microsyst Nanoeng
December 2024
Department of Electrical Engineering and Computer Science, University of Missouri, Columbia, MO, 65211, USA.
A new high-sensitivity, low-cost, Surface Enhanced Raman Spectroscopy (SERS) sensor allows for the rapid multiplex detection of foodborne pathogens in raw poultry. Self-assembled microspheres are used to pattern a hexagonal close-packed array of nanoantennas onto a side-polished multimode fiber core. Each microsphere focuses UV radiation to a photonic nanojet within a layer of photoresist on the fiber which allows the nanoantenna geometry to be controlled.
View Article and Find Full Text PDFEngineered bacteria that self-assemble bioglass polysilicate coatings display enhanced light focusing.
Proc Natl Acad Sci U S A
December 2024
Department of Biology, University of Rochester, Rochester, NY 14627.
Cutting-edge photonic devices frequently rely on microparticle components to focus and manipulate light. Conventional methods used to produce these microparticle components frequently offer limited control of their structural properties or require low-throughput nanofabrication of more complex structures. Here, we employ a synthetic biology approach to produce environmentally friendly, living microlenses with tunable structural properties.
View Article and Find Full Text PDFTopologically protected optical pulling force on synthetic particles through photonic nanojet.
Nanophotonics
January 2024
Institute for Translational Brain Research, MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200032, China.
Article Synopsis
- A dielectric microsphere can gather light into a photonic nanojet (PNJ) that moves towards a near-infrared laser, while it was previously thought Janus particles with a metal layer couldn't stable produce PNJs.
- Researchers found that synthetic Janus particles can also generate a PNJ and experience a backaction force due to their unique composition, even with non-resonant light.
- The study reveals that these Janus particles show a unique hysteresis effect in the backaction force based on laser power changes, suggesting potential applications in manipulating and sorting irregular particles using light.
In this work, we study the imaging performance of microsphere-assisted microscopy (MAM) using microspheres with different refractive indices and immersion conditions under both bright-field illumination (BFI) and dark-field illumination (DFI). The experimental results show that the position of the photonic nanojet of the microsphere plays an important role in MAM imaging. The contrast in imaging is affected by the reflection from the microsphere, the background signal without the microsphere, and the electric field on the substrate surface.
View Article and Find Full Text PDFArticle Synopsis
- This study looks at how to control special light beams called photonic nanojets (PNJs) using cylindrical shapes that can bend light.
- It shows that by using different light styles, we can create different shapes of PNJs, like rod-like and tube-like, which work well even when they are small.
- The findings could help in cool technology like trapping tiny particles and making super-clear images in science and engineering.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!