Generation of highly confined photonic nanojet using crescent-shape refractive index profile in microsphere
| Autor: | P. K. Kushwaha, M. K. Swami, H. S. Patel |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Near and far field 02 engineering and technology Refractive index profile Optical storage 01 natural sciences law.invention 010309 optics symbols.namesake Optics law 0103 physical sciences Electrical and Electronic Engineering Physical and Theoretical Chemistry business.industry 021001 nanoscience & nanotechnology Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials Wavelength symbols Photonics Photolithography 0210 nano-technology business Raman spectroscopy Refractive index |
| Zdroj: | Optics Communications. 415:140-145 |
| ISSN: | 0030-4018 |
| DOI: | 10.1016/j.optcom.2018.01.050 |
| Popis: | Photonic nanojets (PNJs) owing to their sub-wavelength near-field features have found many interesting applications like nanoscopy, nano photolithography, high density optical storage, enhancement of Raman signal and single molecule spectroscopy etc. More recently, the focus of research has been on tailoring of PNJs either for better confinement and thus higher peak intensity or for elongation of nanojet for high resolution far field applications. In this paper, we show that crescent-shape refractive index profile (CSRP) of microspheres can be used to generate highly confined PNJ. By optimizing the refractive index of different layers in CSRP microsphere, we show a free space confinement down to ∼ λ ∕ 4 . 5 (FWHM ∼ 110 nm for excitation with 500 nm wavelength). Further, it was observed that the optical properties of substrates also modulate the PNJ characteristics and lead to a further improvement in the transverse confinement to ∼ λ ∕ 6 . 7 . |
| Databáze: | OpenAIRE |
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