Coupling light into organic nanofibres via Raman scattering: waveguiding properties for near‐infrared light

A technique to couple near‐infrared (IR) light into organic nanofibres that function as active optical waveguides by utilising Raman scattering is developed. Using this technique, light was coupled with λ = 800–910 nm into an organic nanofibre of thiacyanine (TC) dye and waveguiding properties in this wavelength range were investigated. A number of organic nanofibres, including TC nanofibres, have been found to function as active waveguides that propagate their own fluorescence along themselves. The waveguiding properties of these nanofibres have been extensively investigated in their fluorescence wavelength range, which is usually in the ultraviolet to visible region. However, their waveguiding properties outside of the fluorescence range are completely unknown because of the difficulties in coupling light from an external light source. The technique enables coupling of light with various wavelengths from the visible to the near‐IR into nanofibre waveguides and investigation of the waveguiding properties at these wavelengths.