Scalable Fabrication of Fiber-End Microtips Containing Diamond Defects for Sensing Application

We propose a novel and efficient approach to incorporate quantum nanosensors in a tunable microstructure on the end facet of an optical fiber. Specifically, we fabricated a polymer microtip probe containing nanodiamonds using a light-induced self-writing waveguide technique. The shape of the microtips can be modulated by the curing parameters and their corresponding influence on embedded optical defects in nanodiamonds has been numerically and experimentally investigated. With the developed cone-like microtips serving as photonic structures, the introduced resonant peak at 690 nm enhances the fluorescence collection efficiency of incorporated nanodiamonds containing nitrogen vacancy (NV) centers. Based on such a waveguide coupled NV fluorescence, we have found a new avenue for performing all-optical thermometry with improved performance. Considering its easy manufacturing and flexible architecture, our proposed microtip integrated with diamond defects will open up new possibilities for quantum enhanced fiber optic sensing.