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.

scholarly journals Coherent suppression of backscattering in optical microresonators

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Andreas Ø. Svela ◽  
Jonathan M. Silver ◽  
Leonardo Del Bino ◽  
Shuangyou Zhang ◽  
Michael T. M. Woodley ◽  
...  
Keyword(s):  
Quality Factor ◽  
Bulk Material ◽  
Near Field ◽  
High Quality Factor ◽  
Dual Frequency ◽  
High Quality ◽  
Frequency Combs ◽  
Optical Microresonators ◽  
Whispering Gallery ◽  
The Stability

AbstractAs light propagates along a waveguide, a fraction of the field can be reflected by Rayleigh scatterers. In high-quality-factor whispering-gallery-mode microresonators, this intrinsic backscattering is primarily caused by either surface or bulk material imperfections. For several types of microresonator-based experiments and applications, minimal backscattering in the cavity is of critical importance, and thus, the ability to suppress backscattering is essential. We demonstrate that the introduction of an additional scatterer into the near field of a high-quality-factor microresonator can coherently suppress the amount of backscattering in the microresonator by more than 30 dB. The method relies on controlling the scatterer position such that the intrinsic and scatterer-induced backpropagating fields destructively interfere. This technique is useful in microresonator applications where backscattering is currently limiting the performance of devices, such as ring-laser gyroscopes and dual frequency combs, which both suffer from injection locking. Moreover, these findings are of interest for integrated photonic circuits in which back reflections could negatively impact the stability of laser sources or other components.

scholarly journals Palladium and Copper: Advantageous Nanocatalysts for Multi-Step Transformations

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1891
Author(s):  
Antonio Reina ◽  
Trung Dang-Bao ◽  
Itzel Guerrero-Ríos ◽  
Montserrat Gómez
Keyword(s):  
Chemical Properties ◽  
Added Value ◽  
Solid Supports ◽  
Nanosized Materials ◽  
Nano Structures ◽  
Liquid Phases ◽  
Wide Range ◽  
Synthetic Methodologies ◽  
Physical And Chemical ◽  
A Current

Metal nanoparticles have been deeply studied in the last few decades due to their attractive physical and chemical properties, finding a wide range of applications in several fields. Among them, well-defined nano-structures can combine the main advantages of heterogeneous and homogenous catalysts. Especially, catalyzed multi-step processes for the production of added-value chemicals represent straightforward synthetic methodologies, including tandem and sequential reactions that avoid the purification of intermediate compounds. In particular, palladium- and copper-based nanocatalysts are often applied, becoming a current strategy in the sustainable synthesis of fine chemicals. The rational tailoring of nanosized materials involving both those immobilized on solid supports and liquid phases and their applications in organic synthesis are herein reviewed.

Nanostructured optical fibre arrays for high-density biochemical sensing and remote imaging

2009 ◽  
Vol 396 (1) ◽  
pp. 53-71 ◽  
Author(s):  
F. Deiss ◽  
N. Sojic ◽  
D. J. White ◽  
P. R. Stoddart
Keyword(s):  
Optical Fibre ◽  
High Density ◽  
Remote Imaging ◽  
Biochemical Sensing

scholarly journals Scanning Near-Field Optical Microscopy

2008 ◽  
Vol 8 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Dušan Vobornik ◽  
Slavenka Vobornik
Keyword(s):  
Molecular Structure ◽  
Chemical Composition ◽  
Optical Microscopy ◽  
Temporal Resolution ◽  
Dynamic Properties ◽  
Near Field ◽  
Medical Sciences ◽  
Human Eye ◽  
Nano Structures

An average human eye can see details down to 0,07 mm in size. The ability to see smaller details of the matter is correlated with the development of the science and the comprehension of the nature. Today’s science needs eyes for the nano-world. Examples are easily found in biology and medical sciences. There is a great need to determine shape, size, chemical composition, molecular structure and dynamic properties of nano-structures. To do this, microscopes with high spatial, spectral and temporal resolution are required. Scanning Near-field Optical Microscopy (SNOM) is a new step in the evolution of microscopy. The conventional, lens-based microscopes have their resolution limited by diffraction. SNOM is not subject to this limitation and can offer up to 70 times better resolution.

scholarly journals From Far-Field to Near-Field Micro- and Nanoparticle Optical Trapping

2020 ◽  
Vol 10 (4) ◽  
pp. 1375 ◽  
Author(s):  
Theodoros D. Bouloumis ◽  
Síle Nic Chormaic
Keyword(s):  
Optical Tweezers ◽  
Near Field ◽  
Metallic Nanostructures ◽  
Diffraction Limit ◽  
Submicron Particles ◽  
Great Success ◽  
Laser Illumination ◽  
Minimum Particle Size ◽  
Standard Tool ◽  
Established Technique

Optical tweezers are a very well-established technique that have developed into a standard tool for trapping and manipulating micron and submicron particles with great success in the last decades. Although the nature of light enforces restrictions on the minimum particle size that can be efficiently trapped due to Abbe’s diffraction limit, scientists have managed to overcome this problem by engineering new devices that exploit near-field effects. Nowadays, metallic nanostructures can be fabricated which, under laser illumination, produce a secondary plasmonic field that does not suffer from the diffraction limit. This advance offers a great improvement in nanoparticle trapping, as it relaxes the trapping requirements compared to conventional optical tweezers although problems may arise due to thermal heating of the metallic nanostructures. This could hinder efficient trapping and damage the trapped object. In this work, we review the fundamentals of conventional optical tweezers, the so-called plasmonic tweezers, and related phenomena. Starting from the conception of the idea by Arthur Ashkin until recent improvements and applications, we present the principles of these techniques along with their limitations. Emphasis in this review is on the successive improvements of the techniques and the innovative aspects that have been devised to overcome some of the main challenges.

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