Tuning of optical resonances in asymmetric microtube cavities.
ABSTRACT We tune optical resonances in rolled-up SiO/SiO(2) microtube cavities by gradually modifying the tube structure through asymmetrical postdeposition of SiO(2). Spectral blueshifts followed by redshifts of the resonant modes are observed in a thin-walled microtube (tube-I), which is attributed to a competition between shape deformation and effective increase of tube wall thickness. In contrast, only a monotonic redshift is detected when asymmetrical deposition is performed on a thick-walled microtube (tube-II). Distinct wavelength-dependent tuning was revealed in both kinds of tubes. Numerical calculations based on perturbation theory are carried out to explain and confirm the experimental results.
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ABSTRACT: Opto-chemical sensors are prepared by self-assembly of SiO/SiO2 nanomembranes into microtube structures. Dynamic molecular processes of H2 O and C2 H5 OH are detected on the surface of sub-wavelength-thin nanomembranes. Based on perturbation theory, quantitative information of molecule layer changes is acquired. The nanomembrane-based molecular-sensing ability constitutes a versatile platform for the detection of diverse surface phenomena in a label-free fashion.Advanced Materials 03/2013; · 14.83 Impact Factor
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ABSTRACT: Asymmetric cone-like microtube cavities have been fabricated by unevenly rolling-up prestrained SiO/SiO<sub>2</sub>circular-shaped nanomembranes. Spatially localized axial resonant modes are obtained due to an axial confinement mechanism that is defined by the variation of the tube radius and windings along the tube axis. A theoretical model is applied to quantitatively explain and confirm our experimental results.Optics Letters 10/2012; 37(20):4284-6. · 3.39 Impact Factor