Accurate measurement of wavelength-Dependent beam parameters of a supercontinuum light source focused by a lensed fiber probe

• A method to analyze beam parameters of a focused supercontinuum is demonstrated. • All spectral components of the supercontinuum can be analyzed. • Significant errors from conventional method are resolved. In this work, an supercontinuum (SC) light is focused by an optical lensed fiber (OLF). We demonstrate a new method to meticulously analyze multi-wavelength beam parameters of the OLF probe and the focused SC beam by applying a spectrometer to measure the variation of back-coupling efficiency for different wavelengths. By contrast, inevitable and relatively small errors in the OLF parameters that are obtained by using the conventional method lead to significant errors in the spatial information of the focused SC beam. Therefore, this method is expected to be a necessary calibration procedure for a system with an OLF probe. The SC beam focused by our OLF has little chromatic aberration in the beam size and the focal length in a range of approximately 120 μm.