Magnetic skyrmions are nanoscale, topologically protected spin structures with great potential for energy-efficient spintronic devices due to their stability, small size, and low energy consumption. This presentation reviews the fundamental mechanisms of skyrmion formation, particularly exchange interaction and Dzyaloshinskii–Moriya interaction (DMI), along with experimental techniques for their detection and manipulation. It also explores promising applications in racetrack memory.

Commercial blue gallium nitride (GaN) Fabry–Perot laser diodes offer compact and low-cost optical sources for laser spectroscopy. However, multimode emission and mode hopping during wavelength tuning can limit their suitability for applications requiring narrow and stable laser emission. Building on previous work on blue external-cavity diode lasers (ECDLs), this study investigates wavelength-selective optical feedback as a route to improving the spectral and operational performance of low-cost GaN Fabry–Perot laser diodes. Key performance parameters are examined, including linewidth, frequency drift, output power stability, mode-hop-free tuning range, and side-mode suppression ratio (SMSR). An experimental approach based on the Littrow configuration is proposed, with emphasis on optimizing diffraction-grating parameters, optical feedback, polarization, and frequency and power stabilization. The study aims to establish practical design criteria for an affordable, narrowband, tunable, and stable blue laser source suitable for high-resolution laser spectroscopy and optical sensing.

All faculty, researchers and students are invited to attend.