The Fabrication, Fluorescence Dynamics, and Whispering Gallery Modes of Aluminosilicate Microtube Resonators

Abstract

In this paper a novel technique for the production of aluminosilicate microtubes, which are shown to act as optical cylindrical microresonators, is described. The free‐standing microtubes are fabricated by using vacuum‐assisted wetting and filtration of silica gel through a microchannel glass matrix. The microtubes are studied using scanning electron microscopy, micro‐photoluminescence spectroscopy, and fluorescence lifetime imaging confocal microscopy. In the emission spectra of the microresonators we find very narrow periodic peaks corresponding to the whispering gallery modes of two orthogonal polarizations with quality factors up to 3200. A strong enhancement in photoluminescence decay rates at high excitation power demonstrates the occurrence of amplified spontaneous emission from a single microtube. These microtubes show a large evanescent field extending many micrometers beyond the tube radius. Applications for these novel microresonators will be in the areas of microlasers and microsensors and quantum information processing.

Synthesis of Anatase TiO2 Tubular Structures Microcrystallites with a High Percentage of {001} Facets by a Simple One‐Step Hydrothermal Template Process

“…[2][3][4] Owing to their special structures and outstanding mechanical/electrical properties, tubular structures have been widely used for the fabrication of microfluidics and optical devices, biomedical instruments, chemical microreactors, and composite materials. [5][6][7][8][9][10][11][12] So far, various tubular structures have been produced by using vapor phase deposition, lamella structure scroll, template-assisted, metal-catalyst-assisted, and thermal solution methods. [7,[13][14][15][16][17][18] High-aspect-ratio TiO 2 nanotubular layers possess significantly stronger photocatalytic properties than nanoparticulate layers do.…”

Refractometric Sensing of Heavy Oils in Fluorescent Core Microcapillaries

“…The resonances are characterized by: -a higher visibility in the Transverse Electric (TE) polarization (i.e., with the electric field parallel to the capillary axis). This polarization phenomenon is sometimes reported in cylindrical resonators but is not fully understood [19]; -fluorescence Q factors (Q = k peak /Dk peak ) of $500; -a Free Spectral Range (FSR) between fundamental resonances of $ 4.5 nm, which is related mainly to the radius of the channel; -a slight skewing of the resonances toward shorter wavelengths. This skewing effect is consistent with the propagation of spiralling modes having a component of the wavevector parallel to the capillary axis [6,20].…”

Optical microcavities with tubular geometry: properties and applications

“…The mode distributes deeper from the outside boundary and the corresponding cavity Q‐factor decreases, especially for the higher mode order ( l > 1). The second (radial) mode order ( l ) indicates the number of maxima in the radial distribution of the internal electric field .…”

“…On account of the superior optical properties in these microtubular cavities, cell scaffolds, liquid refractive‐index sensors, and low‐threshold microlasers have been produced following the study of the optical resonance in self‐rolled microtubular cavities. With the exception of the self‐rolling method, most traditional techniques involve templates and electrospinning in the fabrication of microdevices or microsystems with good optical performance and promising applications in DNA detection , bio/chemsensing , cell cultures , lasing , and integrated lab‐on‐a‐chip/lab‐in‐a‐tube devices . Development of new fabrication processes and introduction of new materials have brought new functions .…”