Enhancement of two photon fluorescence collection by using effectively single mode double clad hollow core fiber with low dispersion at 800nm
We show that application of the double clad hollow core fiber (DCHCF) significantly affects efficiency of collecting a two photon fluorescence signal. In our approach we propose a new construction of the hollow core double clad fiber which can be used to send simultaneously an ultrafast signal through the single-mode air core and collect the florescence signal through a multimodal clad. The presented fiber has a dispersion equal to 5.13ps/nmkm and losses 0.5dB/m in the range of 800nm. In the wavelengths range between 770 to 850nm the fiber is endlessly single mode with higher order modes HOMs losses above 17dB/m. The use of such a fiber allows elimination of prevalent precompensation dispersion systems and considerably simplifies the two photon fluorescence endoscopy setup.
ultrafast signals fluorescence endoscopy photonic crystal fiber two-photon endoscopy