Polymer-based micro-optical components are very important for applications in optical communication. In this study, we theoretically investigated the coupling of polymeric waveguide and microring structures and experimentally demonstrated an efficient fabrication method to realize these structures on demand. First, the structures were designed and simulated using the FDTD method. The optical mode and loss in the coupling structures were calculated, thereby giving the optimal distance for optical mode coupling between two rib waveguide structures or for optical mode coupling in a microring resonance structure. Simulations results then guided us in the fabrication of the desired ring resonance microstructures using a robust and flexible direct laser writing technique. The entire optical system was thus designed and manufactured on a flat base plate so that it could be easily integrated in optical circuits.

Photonic crystal (PC) is usually realized in materials with high refractive indices contrast to achieve a photonic bandgap (PBG). In this work, we demonstrated an optimization of two-dimensional PCs using a low refractive index polymer material. An original idea of assembly of polymeric multiple rings in a hexagonal configuration allowed us to obtain a circular-like structure with higher symmetry, resulting in a larger PBG at a low refractive index of 1.6. The optical properties of such newly proposed structure are numerically calculated by using finite-difference time-domain (FDTD) method. The proposed structures were realized experimentally by using a direct laser writing technique based on low one-photon absorption method.

Light is generally important for human beings. Visible light supports vision and can modify circadian rhythm, and together with invisible light at longer or shorter wavelength can also make either a direct or indirect impact on human biological and mental health. For medical applications, several studies have shown success in using light to fasten the skin regeneration in burns and to cure diseases such as newborn jaundice. In daily life, an appropriate amount and time exposure to certain types of light can result in rising of alertness and mood improvement, which leads to noticeable growth in one’s productivity. Therefore, human centric lighting can modify lighting factors to make the best of the natural characteristics of light. The seek an ideal indoor lighting system is widely carried out not only by scientists but also by architects. A qualified luminaire is considered by many factors, including luminous productivity, visual comfort and expenses; meanwhile, the idealization of illuminance is also constructed in many ways, such as widening the lamp’s surface area, changing of luminaire’s positions and applying different methods to illuminate a surface. Approaching these problems, our idea is to study the uplighting method and freeform optics using low-cost acrylic lenses. By changing lens shape and optimizing the factors which affect the illuminance such as the irradiation angle and the distance between the luminaire and the reflection surfaces, we find the most effective lens and its peaks due to each factors using the ray-tracing simulation to obtain results concerning high uniformity of illumination.

This study presents the synthesis of NaYF₄: Er³⁺/Yb³⁺ upconversion luminescent nanomaterials using a wet chemistry method. The role of oleic acid in influencing the size, shape, and luminescent properties of the materials was also investigated. The results showed that, at a suitable oleic acid concentration of 10⁻³ M, the obtained nanoparticles exhibited a nearly spherical morphology with diameters ranging from 150 to 250 nm and predominantly display a hexagonal (β-NaYF₄) crystalline phase. Photoluminescence measurements under 980 nm laser excitation reveal that these nanoparticles emit strong, stable luminescence with narrow emission bands characteristic of Er³⁺ transitions. Subsequently, the nanoparticles were coated with a silica shell, functionalized with amine groups, and conjugated with IgG antibodies via glutaraldehyde (GA) to form the bio-nano complex β-NaYF₄: Er³⁺/Yb³⁺@SNGA-IgG. In vitro experiments using fluorescence microscopy demonstrated that the complex effectively labels HeLa cervical cancer cells. With its robust upconversion luminescence and excellent biocompatibility, the developed nanocomplex shows promising potential for rapid pathogen detection and other biomedical applications.

Background: A large number of studies have demonstrated the wound-healing effects of LLLT in vitro, in animal models, and in clinical practice. However, there are also differences in the study results, which are dose and wavelength dependent of LLLT. Objective: Evaluation of the wound healing process in experimental animals treated with low- level laser therapy in clinical and histopathology. Subjects and Methods: Prospective study on 30 rabbits, each rabbit created two full thickness of 2R = 4 cm wounds on both sides of the back: wound A (treated with LLLT, 780 nm, 3 J/cm2 with 72 s irradiation time, 1 time per day), wound B (control: no laser). Wounds are bandaged and laser irradiated once a day according to the procedure until the lesion is completely epithelialized. Wound biopsy was taken at: before treatment (D0), after 7 days (D7), after 14 days (D14) of treatment. Monitor and evaluate progress at the local wound. Results: The area and speed of wound narrowing on the side of the laser site narrowed faster than the control side (p < 0.05). The results of rabbit skin histopathology showed that the number of inflammatory cells on the laser side decreased significantly compared with the non-laser side (p(D14) < 0.05), while the number of neovascular and fibroblasts increased rapidly on the LLLT side when compared with the control side (p(D7) < 0.05). Conclusions: LLLT (780 nm, dose 3J/cm2) increased wound healing in experimental rabbit model. LLLT promotes wound narrowing, reduces inflammation, stimulates angiogenesis, and increases collagen synthesis fibroblasts