Application of Negative Curvature Hollow-Core Fiber in an Optical Fiber Sensor Setup for Multiphoton Spectroscopy. - Maciej Andrzej Popenda; Hanna Izabela Stawska; Leszek Mateusz Mazur; Konrad Jakubowski; Alexey Kosolapov; Anton Kolyadin; Elzbieta Beres-Pawlik (Sensors, 2017)