A fluid-based active plasmonic grating filter

Jun Wu,Tong Zhang,Baoping Wang,Wei Lei,Yaqiong Du,Jun Xia

doi:10.1063/1.5126347

Abstract

An advanced electrowetting fluid manipulation technology is adopted to realize the dynamic redistribution of the surrounding fluid media of silver grating, and thereby, the surface plasmon resonance is real-timely modulated. The results indicated that the wavelength of the resonance absorption peak of the designed fluid-based grating filter can be tuned smoothly and continuously by simply varying the electrowetting voltage. More importantly, the modulation is reversibly operated, fast responded, and energy efficient and can be flexibly integrated. By combining this electrowetting filtering function with the appropriate structural parameters according to the practical demands, such novel design can realize the fine-tuning of light covering the entire visible spectrum.

Highlights

Benefits from the development of nanofabrication and characterization techniques, surface plasmons (SPs), and the related plasmonic nanodevices have attracted much interest during the last decade.1–3 The SPs have been well known as the collective-free electron oscillations excited by an incident electromagnetic wave at the interface of metal and surrounding media
The SP can only propagate at the metal/dielectric interface and decay exponentially away from the interface, it has the unique capability to manipulate the electromagnetic wave at the nanoscale, which is the reason why it has led to numerous intriguing physical phenomena and useful applications
We propose a plasmonic filter that consists of nanogratings filled with two immiscible fluids, water and oil

Summary

Introduction

Benefits from the development of nanofabrication and characterization techniques, surface plasmons (SPs), and the related plasmonic nanodevices have attracted much interest during the last decade. The SPs have been well known as the collective-free electron oscillations excited by an incident electromagnetic wave at the interface of metal and surrounding media. It has shown the capabilities to selectively transmit, absorb, or scatter electromagnetic waves because of the strong resonance of free charges on the metal surface with the electromagnetic wave of a particular wavelength.6 Such phenomena can be well used in many fields and occasions, color display, for instance. The structures of interest in this field are multifarious and include gratings, nanoaperture arrays, nanoantennas, and multilayer systems.10 Such sorts of plasmonic coloring technologies are passive, which means the filtering function is uniquely fixed upon fabrication and lacks efficient modulation means. To satisfy the requirement for the multiband spectral imaging, devices integrated with different nanostructures were designed.11,12 In these devices, two neighboring output stacks must be separated by additional structures or by specific coupling distances, which badly restricted the device dimension and efficiency. The simulation results indicate that the wavelength of the resonance absorption peak of the designed fluid-based grating filter can be tuned smoothly

Methods

Results

Conclusion