The dependence of the spectral position of the lasing line of a microdisk laser with InAs/InGaAs/GaAs quantum dots on the refractive index of an aqueous solution in which the microlaser is immersed ...is studied. A maximum resonance shift of 9.4 nm/RIU was obtained for 10-μm-diameter microlasers immersed in an aqueous glucose solution.
We used thermal poling structuring of glass samples followed by chemical etching and subsequent out-diffusion growth of silver nanoparticles to fabricate periodic arrays of grooves etched in the ...glass with silver nanoparticles at their bottom. A numerical modeling of optical properties of these periodic structures was performed. We demonstrated that they support both plasmon and grating resonances, which interaction provides additional enhancement of an incident electric field. This can increase surface-enhanced Raman scattering by such biresonant structure.
The single mode lasing of microdisks (MDs) with attached antibodies in aqueous medium is demonstrated. MDs comprise quantum dot active region emitting in the vicinity of 1.3 μm. The presence of ...antibodies on a MD surface leads to a number of effects, including the increase of threshold power of laser generation, likewise, changes in the linewidth of the resonance peak.
It has been shown that the additional annealing of thermally poled silicate glasses at temperatures exceeding the glass poling temperature and close to, but below, the glass transition temperature ...leads to an essential decrease of the volume of polarized regions and, as the result, to an increase in the height of the surface relief structures formed by poling with profiled relief anodic electrode. Thermodynamic and rheological explanations of the found volume decrease are given.
•High-temperature annealing of thermally poled silicate glasses leads to a decrease of the volume of poled regions•If poling is performed with structured anode, the annealing results in enhancement of surface relief formed before annealing•Time dependence of the volume decrease obeys the kinetic equation of the first order•Rheological behavior of poled glasses is well described by the model of Kelvin-Voigt rheological body
We present a technique to fabricate SERS substrates fully integrated with microfluidic channels. The fabrication of microsized dielectric channels was based on selective wet etching of a ...poled/unpoled silicate glass while silver nanoisland film was grown on the bottom of the channels via out-diffusion technique. Different combinations of fabrication steps were studied to optimize the channels' depth, formation of the metal nanoislands and the roughness of the channels' bottom.
Lasing of optically pumped semiconductor microdisks immersed in aqueous medium is demonstrated for the first time. Microlasers containing quantum dot active region were placed into the transparent ...polydimethylsiloxane chamber filled with distilled water at room temperature. The spectral and threshold characteristics of the lasers are compared in both air and aqueous environments. We suppose that such high-Q microlasers can be used as highly sensitive biosensors.
It is demonstrated that microdisk lasers about 10 μm in diameter with an active region based on InAs/InGaAs quantum dots synthesized on GaAs substrates can be used for biodetection. Chimeric ...monoclonal antibodies against the CD20 protein that are covalently attached to the surface of microdisk lasers operating in an aqueous medium under optical pumping and room temperature were used as detectable objects. It is shown that the addition of secondary antibodies leads to an increase in the threshold power of laser generation, as well as to an increase in the full width at half maximum (FWHM) of the resonance laser line.
Relief diffraction gratings are formed via acidic chemical etching of a periodically poled soda-lime glass. The thermal poling under 1000 V DC is performed at 325 °C using a thermally stable ...glassy-carbon anodic electrode with periodic grooves, the depth of the grooves being of ∼650 nm. Poling-induced modification of the glass results in deepening the glass anodic surface in the regions under the ribs of the anodic electrode due to volume relaxation and in increasing chemical durability of these regions in acidic media comparatively to the virgin glass. Chemical etching of the poled glass in NH4F:8H2O solution allows additional to the thermal poling shaping of the glass surface via faster dissolution of unpoled/less poled glass regions. The morphology of the glass surface before and after the etching is characterized with atomic force and scanning electron microscopy. About 30 min etching provides the formation of ∼0.9 μm in height relief diffraction gratings with the diffraction efficiency close to the theoretically achievable ∼30% for multi-order diffraction. In vivo measuring of the diffraction efficiency in the course of the etching allows precise fabrication of the gratings.
•Acidic etching of periodically poled glasses forms effective diffraction gratings.•Etching replaces ribs formed after thermal poling by grooves at the same places.•30 min etching provides ∼0.9 μm in height relief grating.•In-vivo measurements of diffraction allows precise fabrication of the gratings.
Quantum-dot microdisk lasers coated with different dielectric layers transparent in spectral diapason of laser radiation were studied. We observe that the coating influences the mode spectra of the ...microlasers, reduces the resonator Q factor and improves their thermal resistance.
Self-organized metal nanostructures have been obtained by an original method on the surface of soda–lime glasses. The nanostructures are grown by heat treatment of poled glass substrates in hydrogen ...upon preliminary ion-exchange introduction of silver. The poling is produced with the aid of a profiled anode electrode. Using the proposed method, it is possible to grow separate metal nanoislands and ordered nanostructures of several islands on the glass surface. The islands are formed in submicron-sized unpoled regions as a result of self-assembly during out-diffusion of silver. Minimum spacing in linear groups of two or three silver islands is 20–30 nm at their characteristic size of about 100 nm. The proposed method allows nanoisland arrays and groups of a few islands to be grown and multiplicated.
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