Confocal scanning optical microscope using single-mode fiber for signal detection.

A single-mode fiber is employed as a detector in a confocal scanning optical microscope (CSOM) instead of a pinhole and its optical property is studied. The optical system is always coherent, which is fundamentally different from the CSOM with a finite-sized pinhole. The coherent transfer function and the axial response are calculated. Experimentally, the coherent image is taken and the axial response is also measured.