Propagating waves in quasi-one dimensional MoO3 ribbons investigated by Raman spectroscopy and scanning near-field optical microscope

MoO₃ ribbons have proven to be a good quasi-one dimensional waveguide. Here, we show that propagating waves can be launched in very thin MoO₃ ribbons with the thickness of only 150 nm. By using Raman image method, it was found that the 1/e light damping length at 632.8 nm is 5 ∼ 6 μm. Scanning near-field optical measurement was carried to provide distribution of propagating waves near the surface of the waveguide, where Fabry-Pérot interference with the period ∼ 0.33 μm was observed. Furthermore, numerical calculations reveal the guiding waves in thin ribbons are in leak mode with a large portion of energy guided over the MoO₃ surface. Applications of these kinds of thin MoO₃ ribbons can be found in combined nano-photonic devices and remote surface enhanced Raman sensing.