Multiphoton microscopy (MPM) is a powerful technique for high resolution imaging of biological tissues. A specially-designed chirped photonic crystal fiber (CPCF) is introduced for MPM applications. The CPCF eliminates most pulse broadening effects in a broad transmission window because its cell-size radial chirp in the cladding structure localizes the reflection of different wavelengths in different resonant layers of the cladding, similar to chirped mirrors. In contrast, traditional hollow core fiber (HCF) consists of several identical reflective layers that produce substantial higher-order dispersion. The feasibility of applying the CPCF for MPM imaging is studied. The propagation properties of the CPCF are characterized by autocorrelation traces measured with and without the CPCF, which confirms an extremely low dispersion of the CPCF. The dispersion from other optics in the MPM imaging system is further compensated by a double-folded prism pair. In the autocorrelation trace measurement, satellite peaks are observed when the length of the CPCF is short (~40 cm), which disappear when the fiber length is chosen sufficiently long. The satellite peaks appear to originate from modal dispersion. With propagation lengths above 1 m, single mode propagation can be achieved in the CPCF. The extremely low dispersion of CPCF over a wide transmission window is promising in MPM applications for the fiber delivery of femtosecond pulses, especially in sub-20fs or tunable laser illumination.

Date Published: 22 February 2013
PDF: 7 pages
Proc. SPIE 8588, Multiphoton Microscopy in the Biomedical Sciences XIII, 85882R (22 February 2013); doi: 10.1117/12.2005644

Published in SPIE Proceedings Vol. 8588:
Multiphoton Microscopy in the Biomedical Sciences XIII
Ammasi Periasamy; Karsten König; Peter T. C. So, Editor(s)