Low loss surface electromagnetic waves on a metal-dielectric waveguide working at short wavelength and aqueous environment

A metal-dielectric waveguide (MDW) structure was presented to generate surface electromagnetic waves (SEWs) suitable for short wavelength (<500 nm) working in aqueous environment. Aluminum thin film was employed to adapt for the short wavelength and silica layer was introduced to form the low loss surface mode, whose energy is mainly confined at silica/water interface. Transfer matrix theory was used to investigate theoretically the above ideas, and the process to design and optimize the structural parameters of the MDW structure for the SEWs was also introduced. Experiments were performed to validate the existence and the low loss nature of the SEWs, and the wavelength of the excited SEW was measurement by a home-built near field scanning system which accords well with the theoretical prediction. This type of SEWs on a MDW structure can be as an alternative to overcome the limitations associated with the traditional metal-type waveguide mode such as surface plasmon polariton, and could be potential for applications like the imaging, bio-sensing, precision measurement, etc.