Orbiting Light Around the Outer Surface of Dielectric Microspheres

2021 ◽  
Author(s):  
Toshihiko Ogura
Keyword(s):  
Raman Spectrum ◽  
Outer Surface ◽  
Total Internal Reflection ◽  
Optical Devices ◽  
Atomic Ions ◽  
Whispering Gallery ◽  
Highly Sensitive ◽  
Evanescent Light ◽  
Dielectric Spheres ◽  
Periodic Changes

Abstract Circulating light in the total internal reflection within dielectric spheres or disks is called the whispering gallery mode (WGM), which by itself is highly sensitive to its surface and capable of detecting viruses and single atomic ions. The detection site of the sensors using WGM is created by the evanescent light from the circulating light inside spheres. On the other hand, there have been no reports of observation or discussion of the light orbiting outside the surface of dielectric microspheres. Here we report light orbiting the outer surface of a dielectric microspheres different from the WGM. We observed anomalously enhanced Raman spectrum at the periphery of 3 μm diameter polystyrene (PS) microspheres on a silicon nitride (SiN) film using Raman microscopy. The wavelength intensity of this enhanced Raman spectrum was accompanied by periodic changes due to interference. These features may lead to the development of high-sensitive sensors and optical devices.

scholarly journals Optical Fibre Micro/Nano Tips as Fluorescence-Based Sensors and Interrogation Probes

Optics ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 213-242 ◽  
Author(s):  
Simone Berneschi ◽  
Andrea Barucci ◽  
Francesco Baldini ◽  
Franco Cosi ◽  
Franco Quercioli ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Optical Fibre ◽  
Near Field ◽  
Optical Devices ◽  
Biochemical Sensors ◽  
Whispering Gallery ◽  
Biochemical Sensing ◽  
Nano Structures ◽  
Microscope Imaging ◽  
Physical And Chemical

Optical fibre micro/nano tips (OFTs), defined here as tapered fibres with a waist diameter ranging from a few microns to tens of nanometres and different tip angles (i.e., from tens of degrees to fractions of degrees), represent extremely versatile tools that have attracted growing interest during these last decades in many areas of photonics. The field of applications can range from physical and chemical/biochemical sensing—also at the intracellular levels—to the development of near-field probes for microscope imaging (i.e., scanning near-field optical microscopy (SNOM)) and optical interrogation systems, up to optical devices for trapping and manipulating microparticles (i.e., optical tweezers). All these applications rely on the ability to fabricate OFTs, tailoring some of their features according to the requirements determined by the specific application. In this review, starting from a short overview of the main fabrication methods used for the realisation of these optical micro/nano structures, the focus will be concentrated on some of their intriguing applications such as the development of label-based chemical/biochemical sensors and the implementation of SNOM probes for interrogating optical devices, including whispering gallery mode microcavities.

A Simulation Study of Plasmonic Substrate for In-Process Measurement of Refractive Index in Nano-Stereolithography

2017 ◽  
Vol 11 (5) ◽  
pp. 772-780 ◽  
Author(s):  
Masaki Michihata ◽  
Deqing Kong ◽  
Kiyoshi Takamasu ◽  
Satoru Takahashi ◽  
◽  
...  
Keyword(s):  
Refractive Index ◽  
Lead Zirconate Titanate ◽  
Value Added ◽  
Lead Zirconate ◽  
Process Measurement ◽  
Sensing Range ◽  
Highly Sensitive ◽  
Surface Nanostructures ◽  
Evanescent Light ◽  
Manufacturing Accuracy

Functional surfaces are in demand for recent value-added products. Stereolithography based on evanescent light has been proposed as a technique to fabricate surface nanostructures, but some fabrication error sources must be addressed. In-process measurement is an essential solution to improve the fabrication performance. For in-process measurement in stereolithography, the refractive index of resin is an inherent parameter for product and condition monitoring. This study proposes the in-process measurement of the refractive index of resin based on surface plasmon resonance (SPR). The optical phase response at SPR is highly sensitive to changes in the refractive index of resin but has a narrow sensing range. Therefore, we propose a substrate with a tunable sensing range using lanthanum-modified lead zirconate titanate (PLZT). The structural design was considered using numerical simulation. The SPR conditions were calculated with regard to thickness combinations of PLZT and metal (Ag) films. Depending on these combinations, a sensing range can be tuned on the order of 10-3to 10-4RIU with a sensitivity of 106rad/RIU. However, to realize these performances, the manufacturing accuracy of Ag thin films must be better than 0.1 nm.

scholarly journals Nonstandard FDTD Simulation-Based Design of CROW Wavelength Splitters

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Naoki Okada ◽  
James B. Cole ◽  
Shigeki Yamada ◽  
Kensuke Ogawa ◽  
Yoshifumi Katayama
Keyword(s):  
Optical Waveguides ◽  
Optical Devices ◽  
Whispering Gallery Modes ◽  
Fdtd Simulation ◽  
High Q ◽  
Whispering Gallery ◽  
Simulation Based Design ◽  
Simulation Based ◽  
Fdtd Simulations ◽  
Difference Time

The finite-difference time-domain (FDTD) algorithm has been used in simulation-based designs of many optical devices, but it fails to reproduce high-Q whispering gallery modes (WGMs). On the other hand, the nonstandard (NS) FDTD algorithm can accurately compute WGMs and can be used to make simulation-based designs of WGM devices. Wavelength splitters using the coupled resonator optical waveguides (CROWs) based on WGM couplings have recently attracted attention because they are potentially ultracompact. In this paper, we design a CROW wavelength splitter using NS FDTD simulations and demonstrate high interchannel extinction ratios of over 20 dB.

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