Experimental limitations such as design complexity and low optical throughput have prevented photonic nanojet (PNJ) and photonic hook (PH) measurements from demonstrating and characterizing the implementation of narrow intense electromagnetic beams generated from dielectric microelements with circular symmetry. Near-fields optical microscopy can mitigate these limitations and still present a capability of detecting a highly localized electromagnetic beam for applications in step-index media. Here we model a localized PNJ and PH formation in step-index media. We show that despite negligible refractive index contrast between the water (nwater=1.33) and silica microcylinder (∼1.1), a formation of PNJ and PH is observed with equivalent performance compared to that of silica microcylinder embedded in air (nair=1). This model features a practical fiber source and silica microcylinder as an auxiliary structure. Simultaneously, we performed experimental characterization of a photonic nanojet generated from an optical fiber and studied the resulting near-fields. Our electromagnetic simulation results are in good agreement with the experimental ones, demonstrating a full width at half maximum (FHWM) with a relative error of 0.64%. This system will make fiber-based nanojet realization and characterization accessible and practical for optics and laser engineering applications, super-resolution imaging, and nanolithography.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10052061 | PMC |
http://dx.doi.org/10.3390/nano13061033 | DOI Listing |
Micromachines (Basel)
December 2024
State Key Laboratory for Manufacturing System Engineering, Xi'an Jiaotong University, Xi'an 710054, China.
Inspired by metasurfaces' control over light fields, this study created a liquid microlens coated with a layer of Au@TiO, Core-Shell nanospheres. Utilizing the surface plasmon resonance (SPR) effect of Au@TiO, Core-Shell nanospheres, and the formation of photonic nanojets (PNJs), this study aimed to extend the imaging system's cutoff frequency, improve microlens focusing, enhance the capture capability of evanescent waves, and utilize nanospheres to improve the conversion of evanescent waves into propagating waves, thus boosting the liquid microlens's super-resolution capabilities. The finite difference time domain (FDTD) method analyzed the impact of parameters including nanosphere size, microlens sample contact width, and droplet's initial contact angle on super-resolution imaging.
View Article and Find Full Text PDFMicrosyst 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 PDFProc Natl Acad Sci U S A
December 2024
Department of Biology, University of Rochester, Rochester, NY 14627.
Nanophotonics
January 2024
Institute for Translational Brain Research, MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200032, China.
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 PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!