scholarly journals Liquid Droplet Microresonators

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 473 ◽  
Author(s):  
Antonio Giorgini ◽  
Saverio Avino ◽  
Pietro Malara ◽  
Paolo De Natale ◽  
Gianluca Gagliardi
Keyword(s):  
Acoustic Waves ◽  
Near Infrared ◽  
Liquid Droplet ◽  
Scattered Light ◽  
Surface Acoustic Waves ◽  
Optical Quality ◽  
Whispering Gallery Modes ◽  
New Paradigm ◽  
Frequency Locking ◽  
Whispering Gallery

We provide here an overview of passive optical micro-cavities made of droplets in the liquid phase. We focus on resonators that are naturally created and suspended under gravity thanks to interfacial forces, illustrating simple ways to excite whispering-gallery modes in various slow-evaporation liquids using free-space optics. Similar to solid resonators, frequency locking of near-infrared and visible lasers to resonant modes is performed exploiting either phase-sensitive detection of the leakage cavity field or multiple interference between whispering-gallery modes in the scattered light. As opposed to conventional micro-cavity sensors, each droplet acts simultaneously as the sensor and the sample, whereby the internal light can detect dissolved compounds and particles. Optical quality factors up to 107–108 are observed in liquid-polymer droplets through photon lifetime measurements. First attempts in using single water droplets are also reported. These achievements point out their huge potential for direct spectroscopy and bio-chemical sensing in liquid environments. Finally, the first experiments of cavity optomechanics with surface acoustic waves in nanolitre droplets are presented. The possibility to perform studies of viscous-elastic properties points to a new paradigm: a droplet device as an opto-fluid-mechanics laboratory on table-top scale under controlled environmental conditions.

Angular-momentum coupling of optical whispering-gallery modes to liquid droplet microresonators

2021 ◽  
Vol 104 (4) ◽  
Author(s):  
Davide D’Ambrosio ◽  
Xavier Zambrana-Puyalto ◽  
Marialuisa Capezzuto ◽  
Antonio Giorgini ◽  
Pietro Malara ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Liquid Droplet ◽  
Whispering Gallery Modes ◽  
Whispering Gallery ◽  
Angular Momentum Coupling ◽  
Momentum Coupling

scholarly journals A Vibrometer Based on Magnetorheological Optical Resonators

Vibration ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 239-249 ◽  
Author(s):  
Edoardo Rubino ◽  
Tindaro Ioppolo
Keyword(s):  
Permanent Magnet ◽  
Quality Factor ◽  
Polyvinyl Chloride ◽  
Optical Quality ◽  
Optical Resonator ◽  
Experimental Results ◽  
Whispering Gallery Modes ◽  
Moving Surface ◽  
Whispering Gallery ◽  
Optical Modes

This paper addresses the feasibility of an optical vibrometer that is based on the shift of the optical modes, also known as whispering gallery modes (WGMs), of a magnetorheological optical resonator. The optical resonator that is used in this study is fabricated by mixing polyvinyl chloride plastisol with magnetically polarizable particles. When a permanent magnet that is located nearby the optical resonator is moved, it induces a perturbation of the morphology of the resonator, due to the magnetostrictive effect. This change in the morphology induces a shift in the optical modes of the resonator. The shift of the optical modes can be related to the displacement of the permanent magnet. The proposed sensor concept is based on monitoring the displacement of a tiny magnet that is attached to a moving surface. The optical quality factor of the resonator used in these studies was of the order of 106. The experimental results show a sensitivity of 0.32 pm/μm and a resolution that is less than 300 nm.

scholarly journals Nonlinear imaging of whispering gallery modes in GaN microwires

2021 ◽  
Vol 2015 (1) ◽  
pp. 012015
Author(s):  
Yury Berdnikov ◽  
Igor Shtrom ◽  
Maria Rozhavskaya ◽  
Wsevolod Lundin ◽  
Nicholas Hendricks ◽  
...  
Keyword(s):  
Optical Microscopy ◽  
Nonlinear Optical ◽  
Near Infrared ◽  
Whispering Gallery Modes ◽  
Far Field ◽  
Green Luminescence ◽  
Nonlinear Optical Microscopy ◽  
Whispering Gallery ◽  
Infrared Excitation ◽  
Nonlinear Imaging

Abstract In this work non-scanning far-field nonlinear optical microscopy is employed to study the whispering gallery modes in tapered GaN microwire resonators. We demonstrate the confinement of whispering gallery modes under near-infrared excitation with the photon energy close to half of GaN bandgap. Our results indicate the enhancement of yellow-green luminescence by whispering gallery modes in GaN microwires.

scholarly journals Surface Acoustic Waves: A New Paradigm for Driving Ultrafast Biomicrofluidics

2009 ◽  
Author(s):  
Leslie Y. Yeo ◽  
James R. Friend
Keyword(s):  
Drug Delivery ◽  
Acoustic Waves ◽  
Sessile Drop ◽  
Surface Acoustic Waves ◽  
Capillary Waves ◽  
Liquid Jets ◽  
Powerful Method ◽  
New Paradigm ◽  
Nodal Lines ◽  
Planar Substrates

Surface acoustic waves (SAWs), which are 10 MHz order surface waves roughly 10 nm in amplitude propagating on the surface of a piezoelectric substrate, can offer a powerful method for driving fast microfluidic actuation and microparticle or biomolecule manipulation. We demonstrate that sessile drops can be linearly translated on planar substrates or fluid can be pumped through microchannels at typically one to two orders of magnitude faster than that achievable through current microfluidic technologies. Micromixing can be induced in the same microchannel in which fluid is pumped using the SAW simply by changing the SAW frequency to superimpose a chaotic oscillatory flow onto the uniform through flow. Strong inertial microcentrifugation for micromixing and particle concentration or separation can also be induced via symmetry-breaking. At low SAW amplitudes below that at which flow commences, the transverse standing wave that arises across the microchannel afford particle aggregation and hence sorting on nodal lines. Other microfluidic manipulations are also possible with the SAW. For example, capillary waves excited on a sessile drop by the SAW can be exploited for microparticle or nanoparticle collection and sorting. At higher amplitudes, the large substrate accelerations drives rapid destabilization of the drop interface giving rise to inertial liquid jets or atomization to produce 1–10 μm monodispersed aerosol droplets. These have significant implications for microfluidic chip mass spectrometry interfacing or pulmonary drug delivery. The atomization also provides a convenient means for the synthesis of 150–200 nm polymer or protein particles or to encapsulate proteins, peptides and other therapeutic molecules within biodegradable polymeric shells for controlled release drug delivery. The atomization of thin films containing polymer solutions, in addition, gives produces a unique regular, long-range spatial polymer spot patterning effect whose size and spacing are dependent on the SAW frequency, thus offering a simple and powerful method for surface patterning without requiring physical or chemical templating.

Whispering gallery modes enhance the near-infrared photoresponse of hourglass-shaped silicon nanowire photodiodes

2019 ◽  
Vol 2 (12) ◽  
pp. 572-579 ◽  
Author(s):  
Kihyun Kim ◽  
Sol Yoon ◽  
Myunghae Seo ◽  
Seungho Lee ◽  
Hyeonsu Cho ◽  
...  
Keyword(s):  
Near Infrared ◽  
Silicon Nanowire ◽  
Whispering Gallery Modes ◽  
Whispering Gallery

Luminescent nanoparticles embedded in TiO2microtube cavities for the activation of whispering-gallery-modes extending from the visible to the near infrared

Nanoscale ◽  
2016 ◽  
Vol 8 (18) ◽  
pp. 9498-9503 ◽  
Author(s):  
Abbas Madani ◽  
Libo Ma ◽  
Shading Miao ◽  
Matthew R. Jorgensen ◽  
Oliver G. Schmidt
Keyword(s):  
Near Infrared ◽  
Whispering Gallery Modes ◽  
Whispering Gallery ◽  
Luminescent Nanoparticles
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