Enhanced anisotropy of the nonlinear absorption in the individual Au nanoparticles functionalized KNbO₃ sub-microwire

High quality and high quantity ultra-long KNbO₃ microwires with diameters of 200 nm to a few microns and lengths up to several milimeters have been synthesized by using a simple solvothermal method. The high purity, ideal length and good transferability make it easy to be transferred to the quartz substrate for further linear and nonlinear optical measurements. Functionalized by plasmonic Au nanoparticles, the as-prepared KNbO₃ sub-microwires exhibited enhanced anisotropy of nonlinear absorption that the polarization ratio of individual Au nanoparticles coated KNbO₃ sub-microwire (ρ=0.32) is two times more than the uncoated one. It is demonstrated that this ultra-long KNbO₃ microwire is an ideal candidate for nanolasers, polarization sensitive photodetector and photo-thermal nanodevices.