Recent progress in nanoplasmonics-based integrated optical micro/nano-systems

Nanoplasmonics deals with the collective oscillation of electrons at the surface of metallic structures at the nanometer scale. It possesses advantages including nanofocusing of electromagnetic waves beyond the optical diffraction limit to enhance local electric field intensity and femtosecond-level relaxation times. With the advances in the fundamental understanding of nanoplasmonics in the past two decades as well as the development of nanofabrication technology, nanoplasmonics has found significant practical applications in life sciences, optical manipulations, and high-speed telecommunications. Many structures for nanoplasmonic optical antennas are demonstrated with a focus on improving electric field intensity and extending working wavelength range. The integration of microelectromechanical systems (MEMS) with nanoplasmonics enables dynamically tunable nanoplasmonic metasurfaces. Meanwhile, the introduction of nanoplasmonic metasurfaces into MEMS systems enhances the performance of MEMS photothermal devices, absorbers, emitters, and equips MEMS photonic device with selectivity. The accurate excitation of, and nanofocusing in nanoplasmonics structures are realized by using photonic waveguide input, while photonic waveguides equipped with nanoplasmonic features present higher modulation speed and perform photodetection/sensing functions in a much smaller footprint. Future developments will mainly involve further enhancements in concentrating the electric field, miniaturization of the well-defined nanoplasmonic structures, and realizing the full integration of nanoplasmonics, MEMS, photonic waveguides, and the advanced electronic system using the standard CMOS fabrication technology toward compact micro/nano-systems. With these developments, handheld portable sensors, compact tunable optical manipulation devices, ultra-high-speed chip-scale modulators with high production volume and low-cost are envisaged for healthcare, Internet-of-Things, and data center applications.