All-optical switching based on plasmon-induced Enhancement of Index of Refraction

Abstract

In quantum optical Enhancement of Index of Refraction (EIR), coherence and quantum interference render the atomic systems to exhibit orders of magnitude higher susceptibilities with vanishing or even negative absorption at their resonances. Here we show the plasmonic analogue of the quantum optical EIR effect in an optical system and further implement this in a linear all-optical switching mechanism. We realize plasmon-induced EIR using a particular plasmonic metasurface consisting of a square array of L-shaped meta-molecules. In contrast to the conventional methods, this approach provides a scheme to modulate the amplitude of incident signals by coherent control of absorption without implementing gain materials or nonlinear processes. Therefore, light is controlled by applying ultra-low intensity at the extreme levels of spatiotemporal localization. In the pursuit of potential applications of linear all-optical switching devices, this scheme may introduce an effective tool for improving the modulation strength of optical modulators and switches through the amplification of input signals at ultra-low power.

Tunable Metasurface Based on Plasmonic Quasi Bound State in the Continuum Driven by Metallic Quantum Wells

“…Free‐space optical signal processing and communication have been developing enormously during the past decades. [ 1–3 ] In this field, the mission of modulation on the amplitude, phase, and polarization is mainly realized by spatial light modulators (SLM). [ 4 ] Wherein, the all‐optical SLM prides itself on a higher operating speed than its electronic counterparts.…”

“…Free-space optical signal processing and communication have been developing enormously during the past decades. [1][2][3] In this field, the mission of modulation on the amplitude, phase, and polarization is mainly realized by spatial light modulators to its large dipole-moment of intersubband transition provided from quantum size effect. [18] Combining the high Q-factor from quasi-BIC and the large nonlinearity of MQWs, the modulation speed and depth are improved effectively and superior to the former BIC-based modulation platforms where the typical modulation speeds are at gigahertz level or the extinction ratios are below 3 dB.…”

Plasma Ignition via High-Power Virtual Perfect Absorption

“…These include a myriad of applications such as optical sensing, optical communication, biomedical imaging, photovoltaics, and energy transfer, each relying heavily on precisely controlling how light interacts with different materials. In this context, coherent perfect absorption (CPA) has significantly improved our control over this process by exciting a scattering matrix zero on the real frequency axis. − This approach enables the efficient development of optical switches and logic gates. , However, recent developments have also shown the potential of controlling optical phenomena in lossless systems, emulating a CPA-like response by manipulating complex frequency plane scattering matrix zeros, giving rise to the concept of virtual perfect absorption (VPA) . VPA allows temporary light storage in the system, which can be released on demand.…”

“…1−3 This approach enables the efficient development of optical switches and logic gates. 4,5 However, recent developments have also shown the potential of controlling optical phenomena in lossless systems, emulating a CPA-like response by manipulating complex frequency plane scattering matrix zeros, giving rise to the concept of virtual perfect absorption (VPA). 6 VPA allows temporary light storage in the system, which can be released on demand.…”

All-optical control of ultrafast plasmon resonances in the pulse-driven extraordinary optical transmission

“…All-optical control of plasmon-based nanophotonic systems is highly desirable for on-chip device manipulation, coherent control of photonic signals, ultrafast optical switching, quantum sensing, and high-resolution optical imaging [1][2][3][4]. It also enables active tuning of nanoscale intense electromagnetic fields supported by surface plasmon resonances (SPR) in metallic nanostructures.…”