We present experimental results on photonic crystal/photonic wire micro-cavity structures that demonstrate further enhancement of the quality-factor (Q-factor) - up to approximately 149,000 - in the fibre telecommunications wavelength range. The Q-values and the useful transmission levels achieved are due, in particular, to the combination of both tapering within and outside the micro-cavity, with carefully designed hole diameters and non-periodic hole placement within the tapered section. Our 2D Finite Difference Time Domain (FDTD) simulation approach shows good agreement with the experimental results.

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Iron oxide nanoparticles are one of the nanocarriers that are suitable for novel drug delivery systems due to low toxicity, biocompatibility, loading capacity, and controlled drug delivery to cancer cells. The purpose of the present study is the synthesis of coated iron oxide nanoparticles for the delivery of sorafenib (SFB) and its effects on cancer cells. In this study, Fe₃O₄ nanoparticles were synthesized by the co-precipitation method, and then sorafenib was loaded onto PEG@Fe₃O₄ nanoparticles. FTIR was used to ensure polyethylene glycol (PEG) binding to nanoparticles and loading the drug onto the nanoshells. A comparison of the mean size and the crystalline structure of nanoparticles was performed by TEM, DLS, and X-ray diffraction patterns. Then, cell viability was obtained by the MTT assay for 3T3 and HepG2 cell lines. According to FT-IR results, the presence of O–H and C–H bands at 3427 cm^–1 and 1420 cm^–1 peak correlate with PEG binding to nanoparticles. XRD pattern showed the cubic spinel structure of trapped magnetite nanoparticles carrying medium. The magnetic properties of nanoparticles were examined by a vibrating-sample magnetometer (VSM). IC₅₀ values at 72 h for treatment with carriers of Fe₃O₄@PEG nanoparticle for the HepG2 cell line was 15.78 μg/mL (p < 0.05). This study showed that Fe₃O₄ nanoparticles coated by polyethylene glycol and using them in the drug delivery process could be beneficial for increasing the effect of sorafenib on cancer cells.

The absorption characteristics of complex medium structures having metasurfaces comprised of columnar nanorods of gold were investigated. In this stream, a periodically arranged assembly of vertical gold nanorods of circular and elliptical cross sections, backed by chromium nanorods of the same cross-sectional size and shape, was considered to be the metasurface, and the comparative features of the absorption characteristics were emphasized. The results exhibit very high absorption corresponding to certain wavelengths in the visible span, and the absorber having elliptical gold nanorods yields a better performance than the one with circular nanorods in terms of the magnitude/smoothness of the absorption peaks.

We present the design, fabrication, and characterization of a microcavity that exhibits simultaneously high transmission and large resonance quality-factor (Q-factor). This microcavity is formed by a single-row photonic crystal (PhC) embedded in a 500-nm-wide photonic wire waveguide - and is based on silicon-on-insulator. A normalized transmission of 85%, together with a Q-factor of 18 500, have been achieved experimentally through the use of carefully designed tapering on both sides of each of the hole-type PhC mirrors that form the microcavity. We have also demonstrated reasonably accurate control of the cavity resonance frequency. Simulation of the device using a three-dimensional finite-difference time-domain approach shows good agreement with the experimental results.