Research Output
Articles
Publication Date: 2025
Nanoscale (20403372)17(9)pp. 5403-5412
Silver-silver iodide (Ag-AgI) films are photosensitive materials in the visible light region. In this work, the colour change in Ag-AgI films under low-power monochromatic laser irradiation is shown, which is due to the size variation of silver nanoparticles (AgNPs) on the AgI thin films. This colour variation depends on the wavelength of the laser beam. In contrast, it is independent of the silver iodide thickness. Laser irradiation is employed not only for the colouration of Ag-AgI films but also for promoting the crystallinity of Ag and AgI in these films. At room temperature and atmospheric pressure, the β-phase and the γ-phase of AgI crystals are formed. The optical and structural changes of the Ag-AgI films with two different thicknesses of silver iodide, before and after laser irradiation, are characterized by synchrotron X-ray diffraction, UV-vis spectrophotometry, and X-ray photoelectron spectroscopy. The growth of silver crystals after laser irradiation is significant, especially in the sample with a thinner AgI film under the irradiation of green and blue laser beams with an energy higher than the bandgap energy. However, in the sample with a thicker film of AgI, the size of the β-phase and the γ-phase of AgI crystals increases faster than that of silver crystals after laser irradiation. This study demonstrated that Ag-AgI films have antibacterial and photocatalytic activities. © 2025 The Royal Society of Chemistry.
Publication Date: 2024
Optics and Laser Technology (00303992)171
Holographic silver nanogratings on the surface and within the volume, which have significant potential for data storage applications, are generated in silver chloride (AgCl) waveguides using a single laser beam exposure. This formation process leverages the interference between the polarized incident wave and the TEm modes propagating inside the AgCl waveguide. These plasmonic nanogratings are anisotropic nanostructures, demonstrating intriguing optical traits such as wavelength-specific linear dichroism and birefringence. The observed linear dichroism and birefringence in the holographic silver nanograting can modify the optical rotation and ellipticity of a probe beam traversing this anisotropic medium. Notably, volume holographic nanogratings function as complex nanogratings with a periodicity exceeding that of the incident wavelength. As a result, upon exposure, these complex nanogratings exhibit discernible light diffraction, while the surface holographic nanogratings do not show any diffraction pattern. Additionally, as the AgCl film thickness is increased and more complex nanogratings are formed within the AgCl waveguides, there is a noted reduction in the resulting birefringence. © 2023 Elsevier Ltd
Publication Date: 2022
ACS Applied Nano Materials (25740970)5(4)pp. 5439-5447
We report the fabrication and properties of ion-exchanged optical waveguides based on low-cost soda-lime glasses embedded with silver ions and nanoparticles. Using the thermal ion-exchange process, we embed silver ions into soda-lime glasses by covering the glasses with different ratios of AgNO3:NaNO3 molten salt (2:98, 4:96, and 6:94) at 350 °C. The ion-exchanged glasses containing silver nanoparticles were characterized by using X-ray fluorescence spectroscopy, UV-visible spectroscopy, the X-ray diffraction technique, X-ray photoelectron spectroscopy, and atomic force microscopy of the surface. It is shown that the ion-exchanged glasses make low-loss optical waveguides. Furthermore, we evaluate the refractive index of ion-exchanged waveguides by laser coupling into the waveguide. For this purpose, the ion-exchanged glasses were coated with a silver chloride thin film loaded with silver nanoparticles (Ag-AgCl). When the Ag-AgCl layer is irradiated by a polarized coherent light beam, silver nanograting is formed on the surface of the ion-exchanged glass, and the light beam is simultaneously coupled into the glass. The line-space of nanograting determines the effective refractive index of the ion-exchanged glass. Although we expected the sample with the highest ratio of AgNO3:NaNO3 salt (6:94) to have the largest refractive index, our results demonstrate that the ion-exchanged sample with 4% AgNO3 has the largest effective refractive index, which is due to the penetration of more silver ions and nanoparticles in the glass matrix. Therefore, it is further demonstrated that using a Ag-AgCl layer on an ion-exchanged waveguide is an effective method for coupling light into the waveguides and measuring its refractive index. The mentioned coupling technique in combination with easily fabricated ion-exchanged waveguide has served as an excellent platform for applications in integrated optical circuits. © 2022 American Chemical Society.
