Fiber chromatic confocal method with a tilt-coupling source module for axial super-resolution.

Current fiber chromatic confocal probes suffer from a low axial resolution. This study proposes a fiber chromatic confocal method with a tilt-coupling source module for axial super-resolution. An annular intensity distribution is generated at the fiber port of the probe by adjusting the tilt-coupling angle between the fiber and source module to reduce the width of the confocal axial response characteristic curve at each wavelength and to enhance the intensity contrast of the spectral signal. Compared with the coaxial coupling state, the developed 21° tilt-coupling state can reduce the FWHM by approximately 17%, and the axial resolution increases by 1.7 times.