A proposal for realization of MIR to NIR up-conversion process based on nano-optomechanical system

Abstract

In this work, a nanoscale optomechanical system driven by optical force resulted from light scattering is designed and demonstrated. The proposed system is able to control and manipulate the propagating light in single-mode waveguides in the structure. The optical part of the guiding wave structure consists of two coupled single-mode optical waveguides and a series of nanogold metallic spheres on a silica substrate. The structure is illuminated with a plane wave with a wavelength of 4.3 μm. The resonance of the nanogold spheres due to the incidence plane wave provides scattering and thus the optical force can be generated and causes the two waveguides to deform and start bending toward each other. The generated optical force has been calculated with a maximum value of 34.37pN/μm/W. The designed system could achieve a maximum waveguide displacement of 963 nm. The change in the power of the incident plane wave allows controlling the displacement of the waveguides hence the amount of the NIR (850 nm) light power coupled between the two waveguides can be controlled. Here, the electromagnetic wave with a wavelength of 850 nm has been utilized to propagate in the single-mode waveguides. The induced optical force changes the distance between the single-mode optical waveguides and this causes the coupling of the optical power (NIR) into another waveguide. By choosing the distance between the two waveguides it is possible to couple any desired fraction of the NIR input light from one waveguide to another. Therefore, any changes in the incident MIR light power will affect and change the distance between the two optical waveguides and thus the NIR coupled light changes accordingly. Finally, we have calculated a linear relationship between the coupled light in NIR band and the incident light power in MIR using the proposed structure and in fact this is an optomechanical up-conversion system.