Electrical Control of Third-Order Nonlinearity Via Fano Interference Achieves Picosecond Tuning in Quantum Systems

The demand for compact, programmable optical components drives innovation in quantum photonics, and researchers are now demonstrating electrical control over key nonlinear properties. Deniz Eren Mol, İbrahim Asrın Üzgüç, and Ulaş Eyüpoğlu, alongside colleagues at their institutions, achieve this by harnessing Fano interference within a nano-plasmonic system. Their work reveals a method for continuously tuning third-order nonlinearity, a crucial element for faster and more efficient quantum computations using continuous variables. By coupling bright plasmon modes to quantum objects and then manipulating these objects with an electric field, the team demonstrates a picosecond-level response time, paving the way for significantly enhanced control and speed in future quantum devices.

Photons, Plasmonics, and Nonlinear Optical Systems

This body of work explores the intersection of quantum photonics, plasmonics, and nonlinear optics, focusing on manipulating light at the nanoscale to create advanced optical devices. Researchers investigate how to combine the benefits of quantum light with the unique properties of plasmonic structures, aiming to enhance light-matter interactions and build more efficient quantum circuits. A central theme is the use of Fano resonance, a phenomenon that dramatically enhances light-matter interactions and allows for precise control of optical properties. The research encompasses several key areas, including quantum information processing, the design of novel plasmonic structures, and the exploration of nonlinear optical phenomena.

Scientists are particularly interested in quantum emitters, such as quantum dots and defects in diamond, and how these can be coupled to plasmonic structures to enhance their performance. Computational modelling plays a crucial role, with researchers employing sophisticated simulations to design and optimize materials and structures. This work suggests a focus on developing integrated quantum-plasmonic devices capable of enhanced light-matter interactions and tunable optical properties, promising new functionalities in quantum information processing, sensing, and imaging. The reliance on computational design and optimization underscores the importance of precise control over materials and structures at the nanoscale.

Fano Interference Enables Ultrafast Optical Tuning

Scientists have developed a new method for creating electrically programmable optical components by harnessing Fano interference within a nonlinear nano-plasmonic system. This approach allows for continuous tuning of third-order nonlinearity, a crucial property for advanced optical gates, with picosecond response times. Researchers achieved this by carefully coupling a broadband plasmon mode to a narrow linewidth quantum object, strategically positioned at the hotspot of a dimer consisting of gold nanoparticles. The team validated their approach with both analytical modelling and rigorous simulations using finite-difference time-domain methods, confirming the theoretical predictions and demonstrating how Fano suppression and enhancement effects arise. Experiments revealed that the level-spacing of the quantum object can be precisely controlled by applying an external voltage, enabling dynamic modulation of optical signals. This innovative method achieves efficient and fast tuning of nonlinear optical properties, paving the way for miniaturized and programmable photonic devices with potential applications in quantum computing and advanced optical communications.

Continuous Tuning of Nanoscale Nonlinear Optics

Scientists have demonstrated a new method for continuously tuning the nonlinear optical response of plasmonic systems, achieving precise control over light-matter interactions at the nanoscale. This work centers on harnessing Fano interference within a nonlinear nano-plasmonic system incorporating quantum objects. Researchers successfully coupled a broad bandwidth plasmon mode to these quantum objects and manipulated their energy levels via the Stark effect, achieving continuous tuning of third-order nonlinearity. Experiments reveal that the team can modulate the intensity of third harmonic generation by three orders of magnitude, demonstrating a remarkably efficient and fast control mechanism with a picosecond response time.

The data confirms that the work is based on exact solutions of the three-dimensional nonlinear Maxwell equations, accurately modelling the complex light propagation and interactions within the system. Further investigations explored the impact of using multiple quantum objects, demonstrating that while Fano enhancement remains strong, the enhancement factor degrades due to retardation effects and phase differences, highlighting the importance of spatial arrangement for optimal performance. This breakthrough delivers a pathway for fast, efficient control over nonlinear optical processes, with potential applications in measurement-based quantum computing.

Fano Interference Enables Fast Optical Tuning

This research demonstrates a new approach to creating electrically programmable optical components using plasmonics and quantum objects. Scientists successfully designed a system where the third-order nonlinearity, crucial for advanced optical gates, can be continuously tuned by manipulating the level-spacing of a quantum object positioned within a nanoscale plasmonic structure. By carefully coupling a broadband plasmon mode to a narrow linewidth quantum object, the team achieved this tuning with a picosecond response time, offering a pathway towards faster and more efficient optical signal processing. The key to this achievement lies in exploiting Fano interference, a phenomenon where the interaction between bright and dark resonances enhances the nonlinear response.

Simulations using detailed modelling of electromagnetic fields confirmed that shifting the quantum object’s level-spacing via an applied voltage effectively controls the intensity of the third harmonic generation. However, the research also highlights the importance of precise positioning; randomly arranging multiple quantum objects degrades the enhancement due to phase differences, emphasizing the need for controlled spatial arrangements in experimental implementations. This research represents a significant step towards miniaturized, electrically programmable photonic devices with potential applications in quantum computing and advanced optical communications. Future work will likely focus on optimizing the spatial extent of the quantum object ensemble and exploring different materials to further enhance the nonlinear response and improve the stability of the system.