A method to detect optical modes from vertical InGaAs nanowires (NWs) using cross-polarization microscopy is presented. Light scattered from the optical modes in the NWs is detected by filtering out the polarized direct reflection with a crossed polarizer. A spectral peak and a valley were seen to red-shift with increasing NW diameter in the measured spectra. The peak was assigned to scattering from the TE optical mode and the valley was an indication of the HE mode, based on finite-element and scattering matrix method simulations. The cross-polarization method can be used to experimentally determine the spectral positions of the TE and HE optical modes. The modes are significantly more visible in comparison to conventional reflectance measurements. The method can be beneficial in the characterization of NW solar cells, light-emitting diodes and lasers where precise mode control is required.
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http://dx.doi.org/10.1038/s41598-017-18193-1 | DOI Listing |
Nanotechnology
January 2025
Walker Department of Mechanical Engineering, The University of Texas at Austin, 204 E. Dean Keeton St., Austin, Texas, 78712-1139, UNITED STATES.
Sapphire is an attractive material in photonic, optoelectronic, and transparent ceramic applications that stand to benefit from surface functionalization effects stemming from micro/nanostructures. Here we investigate the use of ultrafast lasers for fabricating nanostructures in sapphire by exploring the relationship between irradiation parameters, morphology change, and selective etching. In this approach an ultrafast laser pulse is focused on the sapphire substrate to change the crystalline morphology to amorphous or polycrystalline, which is characterized by examining different vibrational modes using Raman spectroscopy.
View Article and Find Full Text PDFNat Chem
January 2025
Department of Chemistry, University of California Irvine, Irvine, CA, USA.
Controlling reaction outcomes through external influences is a central goal in chemistry. Vibrational coupling between molecular vibrations and cavity modes is rapidly emerging as a distinct strategy compared with conventional thermochemical and photochemical methods; however, insight into the fundamental mechanisms remains limited. Here we investigate how vibrational weak and strong coupling in plasmonic nanocavities modifies the thermal dehydration of copper sulfate pentahydrate.
View Article and Find Full Text PDFACS Nano
January 2025
Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States.
Recently, we reported on the simple, scalable synthesis of quantum-confined one-dimensional (1D) lepidocrocite titanate nanofilaments (1DLs). Herein, we show, using solid-state UV-vis spectroscopy, that reducing the concentration of aqueous 1DL colloidal suspensions from 40 to 0.01 g/L increases the band gap energy and light absorption onset of dried filtered films from ≈3.
View Article and Find Full Text PDFBiomed Opt Express
January 2025
Center for Optics, Photonics and Lasers, Department of Physics, Engineering Physics and Optics, Université Laval, 2375 Rue de la Terrasse, Québec, Québec G1V 0A6, Canada.
A miniature electrically tuneable liquid crystal component is used to steer light from -1° to +1° and then to inject into a simple tapered fiber. This allows the generation of various propagation modes, their leakage, and selective illumination of the surrounding medium at different depth levels without using mechanical movements nor deformation. The performance of the device is characterized in a reference fluorescence medium (Rhodamine 6G) as well as in a mouse brain (medullary reticular formation and mesencephalic locomotor regions) during in-vivo experiments as a proof of concept.
View Article and Find Full Text PDFWe introduce a novel, to the best of our knowledge, method to achieve a highly efficient nonreciprocal magnon laser within a spinning cavity optomagnonic system, which integrates a magnon mode and two optical modes. The rotation of the YIG sphere triggers the Barnett effect in the magnon mode and the Sagnac effect in the optical modes. The directional input of a pump light leads to opposite Sagnac-Fizeau frequency shifts in these modes.
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