We investigate ballistic electron transport through a one-dimensional Rashba quantum ring coupled to two quantum point contacts and driven by an off-resonant high-frequency electric field. Based on the Floquet effective Hamiltonian and the scattering matrix formalism, we propose an all-optical spin modulator that operates without external magnetic fields. We demonstrate that the synergy between Floquet engineering and the resonant geometry of the ring enables a full spin-flip transition at significantly reduced driving intensities. This resonant amplification provides an efficient alternative to traditional spin-control methods. Analytical conditions for the transmission peaks are derived, showing that the high-frequency field acts as an “optical flux” that can double the spin conductance magnitude compared to conventional magnetic tuning. Our findings establish the Floquet-Rashba ring as a scalable, intensity-efficient building block for next-generation spintronic circuits. Notably, while the core spin-modulating and switching features operate efficiently at zero external magnetic field, we show that a weak static magnetic flux can be employed as a complementary diagnostic tool to tune and map the coexisting Floquet, geometric, and Aharonov-Bohm interference phases.

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• Optoelectronics
• Quantum interference effects
• Spin-orbit coupling
• Spintronics
• 1-dimensional systems
• Floquet systems
• Quantum rings
• Bloch-Floquet theorem