We report an observation of multi-photon excitation of organic chromophores in microbubble whispering gallery mode resonators. High-Q microbubble resonators were formed by heating a pressurized fused silica capillary to form a hollow bubble that was then filled with liquid. In this work, the microbubble was filled with a solution of Rhodamine 6G dye. The resonator and dye were excited by evanescently coupling continuous wave (CW) light from a 980 nm laser diode using a tapered optical fiber. The two-photon fluorescence of the dye can be seen with pump powers as low as 700 μW.
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http://dx.doi.org/10.1364/OL.39.003098 | DOI Listing |
Bioconjug Chem
January 2025
Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India.
Silica nano/microparticles have generated significant interest for the past decades, emerging as a versatile material with a wide range of applications in photonic crystals, bioimaging, chemical sensors, and catalysis. This study focused on synthesizing silica nano/microparticles ranging from 20 nm to 1.2 μm using the Stöber and modified Stöber methods.
View Article and Find Full Text PDFIn living organisms, the natural motion caused by heartbeat, breathing, or muscle movements leads to the deformation of tissue caused by translation and stretching of the tissue structure. This effect results in the displacement or deformation of the plane of observation for intravital microscopy and causes motion-induced aberrations of the resulting image data. This, in turn, places severe limitations on the time during which specific events can be observed in intravital imaging experiments.
View Article and Find Full Text PDFBiological applications using multiphoton microscopy increasingly seek a larger field of view while maintaining sufficient temporal sampling to observe dynamic biological processes. Multiphoton imaging also requires high numerical aperture microscope objectives to realize efficient non-linear excitation and collection of fluorescence. This combination of low-magnification and high-numerical aperture poses a challenge for system design.
View Article and Find Full Text PDFAdaptive optics (AO) improves the spatial resolution of microscopy by correcting optical aberrations. While its application has been well established in microscopy modalities utilizing a circular pupil, its adaptation to systems with non-circular pupils, such as Bessel-focus two-photon fluorescence microscopy (2PFM) with an annular pupil, remains relatively uncharted. Herein, we present a modal focal AO (MFAO) method for Bessel-focus 2PFM.
View Article and Find Full Text PDFNanotoxicology
January 2025
Infection, Inflammation and Repair, Faculty of Medicine, University of Southampton, Southampton, UK.
The role of surfactant proteins A and D (SP-A and SP-D) in lung clearance and translocation to secondary organs of inhaled nanoparticles was investigated by exposing SP-A and SP-D knockout (AKO and DKO) and wild type (WT) mice nose-only for 3 hours to an aerosol of 20 nm gold nanoparticles (AuNPs). Animals were euthanised at 0-, 1-, 7- and 28-days post-exposure. Analysis by inductively coupled plasma mass spectrometry (ICP-MS) of the liver and kidneys showed that extrapulmonary translocation was below the limits of detection.
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