There are significant challenges accompanied by fabricating a pure crystalline VO₂ (M1) thin film with an abrupt metal to insulator phase change properties. Most fabrication methods yield an amorphous VO₂ thin film that requires a post-annealing process to be converted into crystalline VO₂ (M1). Hence, the thickness of VO₂ (M1) films produced is very limited. In this work, we report the growth of pure VO₂ (M1) crystalline thin films onto a sapphire substrate in an oxygen atmosphere by the femtosecond pulsed laser deposition technique and using vanadium pentoxide (V₂O₅) as an ablation target. The thin films were deposited at substrate temperatures of 25 °C, 400 °C, and 600 °C, which reveal the crystallized structures of VO₂ (M1) without post-annealing. The thin film deposited at a substrate temperature of 600 °C exhibits a sharp and an abrupt metal-to-insulator transition (MIT) at a temperature of 66.0 ± 2.5 °C with nearly four orders of magnitude of the resistivity change (3.5 decades) and a narrow MIT hysteresis width of 3.9 °C. Furthermore, the influence of the substrate temperature, nanoparticle or grain size, and film thickness on the MIT parameters such as sharpness of the transition temperature, hysteresis width, and amplitude are discussed for potential applications of tunable antennas, terahertz planar antennas, and RF-microwave switches.

: Optimisation of femtosecond pulsed laser deposition parameters for the fabrication of silicon thin films is discussed. Substrate temperature, gas pressure and gas type are used to better understand the deposition process and optimise it for the fabrication of high-quality thin films designed for optical and optoelectronic applications.

We report the femtosecond laser (100 fs, 800 nm) ablation properties of Er³⁺ ion doped zinc-sodium tellurite glass. Ablation thresholds in dependence of the beam radius (13.9 and 32.0 μm), pulse number, and Er³⁺ ion dopant concentration have been determined. The ablation rate and crater profile depended on the applied fluence.

Over 17 million people experience a stroke episode annually, with 5.9 million deaths. Stroke is diagnosed by physical tests and neuroimaging which need to be performed quickly to determine if the stroke is caused by ischaemia or haemorrhage. Neuroimaging can reliably confirm bleeding, but many patients with suspected ischaemic stroke (up to 40%) are subsequently confirmed to have alternative pathologies e.g., migraine or seizures (stroke mimics) delaying the transfer of stroke patients to an acute stroke unit for early intervention and treatment. Thus, a simple complimentary blood biomarker test to differentiate stroke patients from non-stroke patients with similar clinical symptoms is essential in prehospital and emergency settings for efficient stroke management and prompt treatment. The current 'Gold Standard' technique for detecting protein biomarkers is complex, time-consuming, and requires automated equipment. In this study, we have developed a proof-of-concept of lanthanide-doped upconversion nanoparticle (UCNP)-based optical biosensor platform for detecting glial fibrillary acidic protein (GFAP), a potential stroke biomarker, in human blood serum. The results show a linear response in photoluminescence quenching of UCNP conjugated GFAP antibody with the increasing concentration of GFAP biomarker in human blood serum. This approach can be used in the ambulance and Emergency Department to quickly diagnose a stroke. In the longer term, such techniques can be integrated into a self-assessment kit to monitor those patients who are at risk after strokes.