  In this work, we demonstrate the use of tapered optical fibers (TOF) to
detect charged particle (ions), irradiated at various energies, fluences and
species. The single mode tapered optical fiber has been used in various sensing
applications in recent times. Here, tapered optical fibers have been exposed to
two different ion species namely Ar+ and N+ at different energies and different
fluences, respectively. The optical spectrum analyzer (OSA) detects the changes
in the free spectral range (FSR), period, and transmission power loss from the
ion beam irradiated TOFs. The change in the refractive index of the cladding
material due to the implanted ions influences the transmission spectra of the
TOFs and we could able to detect ions of energy as low as 80 keV. COMSOL
simulation results are employed to explain the observed changes in spectra. The
ion beams induced surface modification and defect formation as well as the
implantation in TOF have been predicted using Monte Carlo based 3D TRI3DYN
ion-solid interaction simulation and corroborated with other experimental
studies such as scanning electron microscopy and Raman scattering spectroscopy.
Such tapered optical fiber-based detection technique will help to develop
portable device to detect charged particles in space exploration and in nuclear
reactors.
