3D Micro- and nano sensing devices creation on the facets of optical fibers via two-photon lithography

Tiny tips of optical fibers are actually expansive platforms for micro- and nanotechnologies, based on which various micro- and nanoarchitectures made of dielectric or metal materials could be built with different fabrication technologies for special applications, such as refractive index, surface enhanced Raman scattering (SERS), pressure and temperature sensing. As for sensors, optical fibers are suitable for this field because of its peculiar characteristics of flexibility, low-loss, and anti-electromagnetic interference. And, the micro- and nanoarchitectures design on the platforms is evolving from two dimensions to three dimensions. There is more freedom for the design of devices based on three dimensional micro- and nanoarchitectures. Firstly, the physical properties of the architectures become designable, the mechanical properties of a thin film with nano-crinkles on it will be different from a homogenous flat one, even if they are made of the same materials. Secondly, advanced optical structures could be introduced and integrated on the platform to realize devices with better performance. In our lab, a Photonic Professional 3D lithography system from Nanoscribe GmbH is employed to create 3D micro- and nano devices on the facets of optical fibers for sensing applications. A SERS radar configuration consisting of a parabolic mirror and a 3D spherical SERS body is created on the end facet of a multimode optical fiber for SERS sensing,a miniaturized optical fiber microphones (vibration sensor) is created by fabricating a concentric nanorings grating and microsprings structured half spherical diaphragm on the end facet of a single-mode fiber for vibration sensing, and surface plasmon resonance refractive index sensors based on multicore optical fibers are developing.