Optically assisted ultrafast spintronics: A review

All-optical switching (AOS) has emerged as a promising technique, utilizing ultrafast lasers with femto or picosecond-pulse durations for modulating magnetization without the use of magnetic fields. This article reviews the state-of-the-art in AOS, focusing on achieving sub-picosecond magnetization reversal in a diverse range of materials, including ferri-magnetic alloys, synthetic ferri-magnets, ferromagnetic multilayers, Heusler alloys, and 2D materials. These materials exhibit remarkable potential for the development of optically driven spintronics devices, offering ultrafast and energy-efficient solutions for circuits and systems, and promising avenues for future photonic integrated circuits. This article also delves into recent advances in opto-spintronic devices, examining their utilization in energy-efficient memory, logic circuits, neuromorphic computing, and terahertz applications. Despite the promising prospects, the integration of opto-spintronic systems into mainstream microelectronic platforms faces several challenges. This review comprehensively discusses these challenges at both the device and system levels, offering insights into potential solutions and future perspectives. By consolidating recent developments and identifying ongoing challenges, this review aims to contribute to the understanding and advancement of AOS in the context of opto-spintronics, paving the way for the next generation of ultrafast and energy-efficient spintronic devices.