A double-clad fiber coupler is developed to be used in two-photon-excited fluorescence endomicroscopy to replace a dichroic mirror and separate the fluorescence signal from the excitation laser beam. With the double-clad fiber coupler, the endomicroscope becomes more compact, easier to be aligned, and more stable in alignment. The double-clad fiber coupler can transmit 62% of the excitation laser beam through the core. The fluorescence collection efficiency of the double-clad fiber coupler is 34%, which is, to the best of our knowledge, the highest fluorescence collection efficiency achieved by couplers used in two-photon-excited fluorescence endomicroscopes. As a result, the contrast of endomicroscopy imaging is enhanced.
© 2010 Optical Society of America
Original Manuscript: December 2, 2009
Revised Manuscript: February 8, 2010
Manuscript Accepted: February 19, 2010
Published: March 26, 2010
Vol. 5, Iss. 8 Virtual Journal for Biomedical Optics
Hongchun Bao, Seon Young Ryu, Byeong Ha Lee, Wei Tao, and Min Gu, "Nonlinear endomicroscopy using a double-clad fiber coupler," Opt. Lett. 35, 995-997 (2010)