Research Projects

With growing demand for ultra-fast, compact, and high-capacity communication systems, quantum technologies are emerging as the next frontier. To meet these demands, the focus is shifting toward quantum technologies, which offer unprecedented capabilities in computation, communication, and data storage. Among these, hybrid quantum systems—where quantum states are coherently transferred across different physical platforms—offer significant potential. Photon–magnon coupling (PMC), the strong interaction between electromagnetic (photons) and spin-wave (magnons) quanta, merges the high-speed benefits of photonics with the nanoscale scalability and rich dynamics of magnonics. PMC-based systems are uniquely tunable via external magnetic fields or internal anisotropy and exhibit nonreciprocal behavior, enabling unidirectional, noise-resilient quantum information flow. A major challenge in realizing magnonic hybrid systems is maintaining long quantum coherence, limited by magnetic damping (α). To date, most demonstrations use bulk or epitaxial YIG, known for low damping (~10⁻⁵), but such systems lack scalability. Achieving efficient PMC requires intimate contact between magnetic films and microwave resonators, ideally through direct patterning on CMOS-compatible substrates. While magnetic thin films are promising for integrated magnonic resonators and waveguides, low-damping metallic magnetic materials remain insufficiently explored and optimized for scalable quantum applications. To overcome current limitations, this project aims to develop low-damping metallic magnetic thin films suitable for compact, on-chip magnonic resonators for quantum information processing devices. The objectives include: (i) synthesizing ultra-low damping magnetic alloys to improve magnon coherence; (ii) developing integrated on-chip hybrid systems using these films to enable photon–magnon coupling (PMC); (iii) engineering geometries to tune PMC dynamics; (iv) formulating quantum models to understand coherent magnon–photon interactions; (v) establishing CMOS-compatible technologies; and (vi) demonstrating quantum coherence in prototype devices. We will focus on Fe₇₀Co₃₀ alloys, prepared by RF magnetron sputtering, due to their high saturation magnetization favorable for PMC. However, their relatively high damping (α ~ 10⁻²) limits quantum applications. To reduce damping, we will alloy FeCo with B, C, or Si, promoting amorphous structures, and optimize the Co:Fe ratio. Additionally, Heusler alloys such as Co₂Mn₀.₆Fe₀.₄Si and Co₂FeAl will be explored for their potential low damping at room temperature and compatibility with on-chip integration. Once optimal films are prepared, magnonic meta-structures will be lithographically patterned on microwave resonators. The structures will be designed using CST Studio or COMSOL to operate in target microwave frequency ranges. PMC will be characterized via transmission spectra using a vector network analyzer under varying magnetic fields. We will also investigate broadband nonreciprocity for relevance in quantum and classical microwave systems. To support experimental results, analytical models based on Quantum theories using Heisenberg–Langevin and master equations will describe strong coupling and nonreciprocal effects between photon and magnon modes. Finally, we aim to realize multimode coupling in hybrid systems, enabling photon-mediated interaction between distant magnons or vice versa. Demonstrating coherence in these configurations will pave the way for magnon-based quantum simulators and fast, tunable, nonreciprocal quantum devices. The proposed research on PMC in On-Chip Hybrid Magnonic presents a suite of novel contributions that push the frontier of integrated quantum technologies. These advances could serve as a significant