Quantification of 288 K local photothermal heating and miniaturization in Si plasmonic waveguides integrated with resonators

Abstract

We report the design and fabrication of Si plasmonic waveguide local heaters with ring resonators. Quantification of the local temperature rise is reported through analysis based on the thermo-optic effect, and the heaters can be miniaturized by introducing a stronger interaction between the propagating light and matter. The resonance wavelength in the waveguide heater was shifted toward a longer wavelength by injecting TM mode light, and the shift was proportional to the light intensity. The local temperature rise was 288 K upon inputting 6.3 mW light, and the photothermal conversion efficiency was as high as 46.1 K mW−1 in a Si plasmonic waveguide loaded with 30 nm thick and 1 μm long Co thin films, showing improved characteristics compared with previous devices. Investigation toward achieving a higher efficiency is discussed based on simulation and experimental results, for realizing photothermal waveguide heaters with smaller sizes and lower input power for various applications.