A design challenge for photodiodes yielding both high speed and responsivity is the necessity to concentrate incident light into a subwavelength active volume region. Photonic nanojets have been reported in the literature as a means to focus an incident plane wave to a subwavelength-waist propagating beam with applications ranging from next-generation DVDs to characterizing subwavelength features within dielectric targets. In the present work, a new application of photonic nanojets is proposed, focusing electromagnetic energy into a photodiode. Three-dimensional finite-difference time-domain solutions are conducted to determine the advantages of photonic nanojet-enhanced photodiodes at near-infrared wavelengths (1310 nm). We find that photonic nanojets provide a factor of 26 increase in the volume-integrated electric field within the subwavelength active volume of the photodiode of size 0.0045 μm³. Furthermore, this increase is achieved independent of the incident polarization and over a broad bandwidth. Photonic nanojets may thus serve as an attractive alternative to plasmonics for some applications.
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http://dx.doi.org/10.1364/AO.52.005420 | DOI Listing |
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 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.
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