Abstract

We demonstrate a dual-band continuum light source centered at 830 and 1300nm for optical coherence tomography (OCT) generated by pumping a photonic crystal fiber having two closely spaced zero-dispersion wavelengths with a femtosecond laser at 1059nm. By use of polarization control, sidelobe suppression can be improved up to approximately 7.7 dB. By employing compression of the pump pulses, the generated spectrum is smooth and near-Gaussian, resulting in a point-spread function with negligible sidelobes. We demonstrate ultrahigh-resolution OCT imaging of biological tissue in vivo and in vitro using this light source and compare it with conventional-resolution OCT imaging at 1300nm.

© 2007 Optical Society of America

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  1. I. Hartl, X. D. Li, C. Chudoba, R. K. Ghanta, T. H. Ko, J. G. Fujimolo, J. K. Ranka, and R. S. Windeler, "Ultrahigh-resolution optical coherence tomography using continuum generation in an air silica microstructure optical fiber," Opt. Lett. 26, 608-610 (2001).
    [CrossRef]
  2. D. L. Marks, A. L. Oldenburg, J. J. Reynold, and S. A. Boppart, "Study of an ultrahigh-numerical-aperture fiber continuum generation source for optical coherence tomography," Opt. Lett. 27, 2010-2012 (2002).
    [CrossRef]
  3. B. Povazay, K. Bizheva, A. Unterhuber, B. Hermann, H. Sattmann, A. F. Fercher, W. Drexler, A. Apolonski, W. J. Wadsworth, J. C. Knight, P. S. J. Russell, M. Vetterlein, and E. Scherzer, "Submicrometer axial resolution optical coherence tomography," Opt. Lett. 27, 1800-1802 (2002).
    [CrossRef]
  4. K. Bizheva, B. Povazay, B. Hermann, H. Sattmann, W. Drexler, M. Mei, R. Holzwarth, T. Hoelzenbein, V. Wacheck, and H. Pehamberger, "Compact, broad-bandwidth fiber laser for sub-2- m m axial resolution optical coherence tomography in the 1300 nm wavelength region," Opt. Lett. 28, 707-709 (2003).
    [CrossRef] [PubMed]
  5. I. Hartl, A. M. Kowalevicz, P.-L. Hsiung, T. H. Ko, T. Schibli, F. X. Kärtner, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Bünting, and D. Kopf, "Ultrahigh resolution optical coherence tomography using novel femtosecond laser sources," in Ultrafast Phenomena XIII, R. D. Miller, M. M. Murnane, N.F. Scherer, and A. M. Weiner, eds. (Springer-Verlag, 2003), pp. 660-662.
  6. N. R. Newbury, B. R. Washburn, K. L. Corwin, and R. S. Windeler, "Noise amplification during supercontinuum generation in microstructure fiber," Opt. Lett. 28, 944-946 (2003).
    [CrossRef] [PubMed]
  7. S. Bourquin, A. D. Aguirre, I. Hartl, P. Hsiung, T. H. Ko, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Büting, and D. Kopf, "Ultrahigh resolution real time OCT imaging using a compact femtosecond Nd:Glass laser and nonlinear fiber," Opt. Express 11, 3290-3297 (2003).
    [CrossRef] [PubMed]
  8. K. M. Hilligsøe, T. Andersen, H. Paulsen, C. Nielsen, K. Mflμer, S. Keiding, R. Kristiansen, K. Hansen, and J. Larsen, "Supercontinuum generation in a photonic crystal fiber with two zero dispersion wavelengths," Opt. Express 12, 1045-1054 (2004).
    [CrossRef] [PubMed]
  9. H. Wang and A. M. Rollins, "Dual band supercontinuum light source for OCT," in Biomedical Optics 2006 Technical Digest (Optical Society of America, 2006), Tui30.
  10. A. Aguirre, N. Nishizawa, J. Fujimoto, W. Seitz, M. Lederer, and D. Kopf, "Continuum generation in a novel photonic crystal fiber for ultrahigh resolution optical coherence tomography at 800 nm and 1300 nm," Opt. Express 14, 1145-1160 (2005).
    [CrossRef]
  11. A. Proulx, J.-M., Ménard, N. Hô, J. M. Laniel, R. Vallée, and C. Paré, "Intensity and polarization dependences of the supercontinuum generation in birefringent and highly nonlinear microstructured fibers," Opt. Express 11, 3338-3345 (2003).
    [CrossRef] [PubMed]
  12. Z. Zhu and T. G. Brown, "Experimental studies of polarization properties of supercontinua generated in a birefringent photonic crystal fiber," Opt. Express 12, 791-796 (2004).
    [CrossRef] [PubMed]
  13. G. P. Agrawal, Nonlinear Fiber Optics (Academic, 2001).
  14. S. Popov, E. Vanin, and G. Jacobsen, "Polarization dependence of gain in discrete Raman amplifiers with dispersion compensating fibres," J. Opt. A 4, 46-51 (2002).
    [CrossRef]
  15. I.-K. Hwang, Y.-J. Lee, and Y.-H. Lee, "Birefringence induced by irregular structure in photonic crystal fiber," Opt. Express 11, 2799-2806 (2003).
    [CrossRef] [PubMed]
  16. P. L. Francois, "Nonlinear propagation of ultrashort pulses in optical fibers: total field formulation in the frequency domain," J. Opt. Soc. Am. B 8, 276-293 (1991).
    [CrossRef]
  17. G. Boyer, "High-power femtosecond-pulse reshaping near the zero-dispersion wavelength of an optical fiber," Opt. Lett. 24, 945-947 (1999).
    [CrossRef]
  18. T. Hori, N. Nishizawa, T. Goto, and M. Yoshida, "Experimental and numerical analysis of widely broadened supercontinuum generation in highly nonlinear dispersion-shifted fiber with a femtosecond pulse," J. Opt. Soc. Am. B 21, 1969-1980 (2004).
    [CrossRef]
  19. M. H. Frosz, P. Falk, and O. Bang, "The role of the second zero-dispersion wavelength in generation of supercontinua and bright-bright soliton-pairs across the zero-dispersion wavelength," Opt. Express 13, 6181-6192 (2005).
    [CrossRef] [PubMed]
  20. Y. Zaouter, J. Didierjean, F. Balembois, G. L. Leclin, F. Druon, P. Georges, J. Petit, P. Goldner, and B. Viana, "47-fs diode-pumped Yb3+:CaGdAlO4 laser," Opt. Lett. 31, 119-121 (2006).
    [CrossRef] [PubMed]
  21. J. R. Buckley, S. W. Clark, and F. W. Wise, "Generation of ten-cycle pulses from an ytterbium fiber laser with cubic phase-compensation," Opt. Lett. 31, 1340-1342 (2006).
    [CrossRef] [PubMed]
  22. P. Herz, Y. Chen, A. Aguirre, J. Fujimoto, H. Mashimo, J. Schmitt, A. Koski, J. Goodnow, and C. Petersen, "Ultrahigh resolution optical biopsy with endoscopic optical coherence tomography," Opt. Express 12, 3532-3542 (2004).
    [CrossRef] [PubMed]
  23. B. E. Bouma, G. J. Tearney, I. P. Bilinsky, B. Golubovic, and J. G. Fujimoto, "Self-phase-modulated Kerr-lens mode-locked Cr:forsterite laser source for optical coherence tomography," Opt. Lett. 21, 1839-1841 (1996).
    [CrossRef] [PubMed]

2006 (2)

2005 (2)

2004 (4)

2003 (5)

2002 (3)

2001 (1)

1999 (1)

1996 (1)

1991 (1)

Agrawal, G. P.

G. P. Agrawal, Nonlinear Fiber Optics (Academic, 2001).

Aguirre, A.

Aguirre, A. D.

Andersen, T.

Apolonski, A.

Balembois, F.

Bang, O.

Bilinsky, I. P.

Birks, T. A.

S. Bourquin, A. D. Aguirre, I. Hartl, P. Hsiung, T. H. Ko, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Büting, and D. Kopf, "Ultrahigh resolution real time OCT imaging using a compact femtosecond Nd:Glass laser and nonlinear fiber," Opt. Express 11, 3290-3297 (2003).
[CrossRef] [PubMed]

I. Hartl, A. M. Kowalevicz, P.-L. Hsiung, T. H. Ko, T. Schibli, F. X. Kärtner, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Bünting, and D. Kopf, "Ultrahigh resolution optical coherence tomography using novel femtosecond laser sources," in Ultrafast Phenomena XIII, R. D. Miller, M. M. Murnane, N.F. Scherer, and A. M. Weiner, eds. (Springer-Verlag, 2003), pp. 660-662.

Bizheva, K.

Boppart, S. A.

Bouma, B. E.

Bourquin, S.

Boyer, G.

Brown, T. G.

Buckley, J. R.

Bünting, U.

I. Hartl, A. M. Kowalevicz, P.-L. Hsiung, T. H. Ko, T. Schibli, F. X. Kärtner, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Bünting, and D. Kopf, "Ultrahigh resolution optical coherence tomography using novel femtosecond laser sources," in Ultrafast Phenomena XIII, R. D. Miller, M. M. Murnane, N.F. Scherer, and A. M. Weiner, eds. (Springer-Verlag, 2003), pp. 660-662.

Büting, U.

Chen, Y.

Chudoba, C.

Clark, S. W.

Corwin, K. L.

Didierjean, J.

Drexler, W.

Druon, F.

Falk, P.

Fercher, A. F.

Francois, P. L.

Frosz, M. H.

Fujimolo, J. G.

Fujimoto, J.

Fujimoto, J. G.

S. Bourquin, A. D. Aguirre, I. Hartl, P. Hsiung, T. H. Ko, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Büting, and D. Kopf, "Ultrahigh resolution real time OCT imaging using a compact femtosecond Nd:Glass laser and nonlinear fiber," Opt. Express 11, 3290-3297 (2003).
[CrossRef] [PubMed]

B. E. Bouma, G. J. Tearney, I. P. Bilinsky, B. Golubovic, and J. G. Fujimoto, "Self-phase-modulated Kerr-lens mode-locked Cr:forsterite laser source for optical coherence tomography," Opt. Lett. 21, 1839-1841 (1996).
[CrossRef] [PubMed]

I. Hartl, A. M. Kowalevicz, P.-L. Hsiung, T. H. Ko, T. Schibli, F. X. Kärtner, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Bünting, and D. Kopf, "Ultrahigh resolution optical coherence tomography using novel femtosecond laser sources," in Ultrafast Phenomena XIII, R. D. Miller, M. M. Murnane, N.F. Scherer, and A. M. Weiner, eds. (Springer-Verlag, 2003), pp. 660-662.

Georges, P.

Ghanta, R. K.

Goldner, P.

Golubovic, B.

Goodnow, J.

Goto, T.

Hansen, K.

Hartl, I.

Hermann, B.

Herz, P.

Hilligsøe, K. M.

Hô, N.

Hoelzenbein, T.

Holzwarth, R.

Hori, T.

Hsiung, P.

Hsiung, P.-L.

I. Hartl, A. M. Kowalevicz, P.-L. Hsiung, T. H. Ko, T. Schibli, F. X. Kärtner, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Bünting, and D. Kopf, "Ultrahigh resolution optical coherence tomography using novel femtosecond laser sources," in Ultrafast Phenomena XIII, R. D. Miller, M. M. Murnane, N.F. Scherer, and A. M. Weiner, eds. (Springer-Verlag, 2003), pp. 660-662.

Hwang, I.-K.

Jacobsen, G.

S. Popov, E. Vanin, and G. Jacobsen, "Polarization dependence of gain in discrete Raman amplifiers with dispersion compensating fibres," J. Opt. A 4, 46-51 (2002).
[CrossRef]

Kärtner, F. X.

I. Hartl, A. M. Kowalevicz, P.-L. Hsiung, T. H. Ko, T. Schibli, F. X. Kärtner, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Bünting, and D. Kopf, "Ultrahigh resolution optical coherence tomography using novel femtosecond laser sources," in Ultrafast Phenomena XIII, R. D. Miller, M. M. Murnane, N.F. Scherer, and A. M. Weiner, eds. (Springer-Verlag, 2003), pp. 660-662.

Keiding, S.

Knight, J. C.

Ko, T. H.

Kopf, D.

A. Aguirre, N. Nishizawa, J. Fujimoto, W. Seitz, M. Lederer, and D. Kopf, "Continuum generation in a novel photonic crystal fiber for ultrahigh resolution optical coherence tomography at 800 nm and 1300 nm," Opt. Express 14, 1145-1160 (2005).
[CrossRef]

S. Bourquin, A. D. Aguirre, I. Hartl, P. Hsiung, T. H. Ko, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Büting, and D. Kopf, "Ultrahigh resolution real time OCT imaging using a compact femtosecond Nd:Glass laser and nonlinear fiber," Opt. Express 11, 3290-3297 (2003).
[CrossRef] [PubMed]

I. Hartl, A. M. Kowalevicz, P.-L. Hsiung, T. H. Ko, T. Schibli, F. X. Kärtner, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Bünting, and D. Kopf, "Ultrahigh resolution optical coherence tomography using novel femtosecond laser sources," in Ultrafast Phenomena XIII, R. D. Miller, M. M. Murnane, N.F. Scherer, and A. M. Weiner, eds. (Springer-Verlag, 2003), pp. 660-662.

Koski, A.

Kowalevicz, A. M.

I. Hartl, A. M. Kowalevicz, P.-L. Hsiung, T. H. Ko, T. Schibli, F. X. Kärtner, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Bünting, and D. Kopf, "Ultrahigh resolution optical coherence tomography using novel femtosecond laser sources," in Ultrafast Phenomena XIII, R. D. Miller, M. M. Murnane, N.F. Scherer, and A. M. Weiner, eds. (Springer-Verlag, 2003), pp. 660-662.

Kristiansen, R.

Laniel, J. M.

Larsen, J.

Leclin, G. L.

Lederer, M.

Lee, Y.-H.

Lee, Y.-J.

Li, X. D.

Marks, D. L.

Mashimo, H.

Mei, M.

Ménard, J.-M.

Mflµer, K.

Newbury, N. R.

Nielsen, C.

Nishizawa, N.

Oldenburg, A. L.

Paré, C.

Paulsen, H.

Pehamberger, H.

Petersen, C.

Petit, J.

Popov, S.

S. Popov, E. Vanin, and G. Jacobsen, "Polarization dependence of gain in discrete Raman amplifiers with dispersion compensating fibres," J. Opt. A 4, 46-51 (2002).
[CrossRef]

Povazay, B.

Proulx, A.

Ranka, J. K.

Reynold, J. J.

Rollins, A. M.

H. Wang and A. M. Rollins, "Dual band supercontinuum light source for OCT," in Biomedical Optics 2006 Technical Digest (Optical Society of America, 2006), Tui30.

Russell, P. S. J.

Sattmann, H.

Scherzer, E.

Schibli, T.

I. Hartl, A. M. Kowalevicz, P.-L. Hsiung, T. H. Ko, T. Schibli, F. X. Kärtner, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Bünting, and D. Kopf, "Ultrahigh resolution optical coherence tomography using novel femtosecond laser sources," in Ultrafast Phenomena XIII, R. D. Miller, M. M. Murnane, N.F. Scherer, and A. M. Weiner, eds. (Springer-Verlag, 2003), pp. 660-662.

Schmitt, J.

Seitz, W.

Tearney, G. J.

Unterhuber, A.

Vallée, R.

Vanin, E.

S. Popov, E. Vanin, and G. Jacobsen, "Polarization dependence of gain in discrete Raman amplifiers with dispersion compensating fibres," J. Opt. A 4, 46-51 (2002).
[CrossRef]

Vetterlein, M.

Viana, B.

Wacheck, V.

Wadsworth, W. J.

Wang, H.

H. Wang and A. M. Rollins, "Dual band supercontinuum light source for OCT," in Biomedical Optics 2006 Technical Digest (Optical Society of America, 2006), Tui30.

Washburn, B. R.

Windeler, R. S.

Wise, F. W.

Yoshida, M.

Zaouter, Y.

Zhu, Z.

J. Opt. A (1)

S. Popov, E. Vanin, and G. Jacobsen, "Polarization dependence of gain in discrete Raman amplifiers with dispersion compensating fibres," J. Opt. A 4, 46-51 (2002).
[CrossRef]

J. Opt. Soc. Am. B (2)

Opt. Express (8)

P. Herz, Y. Chen, A. Aguirre, J. Fujimoto, H. Mashimo, J. Schmitt, A. Koski, J. Goodnow, and C. Petersen, "Ultrahigh resolution optical biopsy with endoscopic optical coherence tomography," Opt. Express 12, 3532-3542 (2004).
[CrossRef] [PubMed]

M. H. Frosz, P. Falk, and O. Bang, "The role of the second zero-dispersion wavelength in generation of supercontinua and bright-bright soliton-pairs across the zero-dispersion wavelength," Opt. Express 13, 6181-6192 (2005).
[CrossRef] [PubMed]

I.-K. Hwang, Y.-J. Lee, and Y.-H. Lee, "Birefringence induced by irregular structure in photonic crystal fiber," Opt. Express 11, 2799-2806 (2003).
[CrossRef] [PubMed]

S. Bourquin, A. D. Aguirre, I. Hartl, P. Hsiung, T. H. Ko, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Büting, and D. Kopf, "Ultrahigh resolution real time OCT imaging using a compact femtosecond Nd:Glass laser and nonlinear fiber," Opt. Express 11, 3290-3297 (2003).
[CrossRef] [PubMed]

K. M. Hilligsøe, T. Andersen, H. Paulsen, C. Nielsen, K. Mflμer, S. Keiding, R. Kristiansen, K. Hansen, and J. Larsen, "Supercontinuum generation in a photonic crystal fiber with two zero dispersion wavelengths," Opt. Express 12, 1045-1054 (2004).
[CrossRef] [PubMed]

A. Aguirre, N. Nishizawa, J. Fujimoto, W. Seitz, M. Lederer, and D. Kopf, "Continuum generation in a novel photonic crystal fiber for ultrahigh resolution optical coherence tomography at 800 nm and 1300 nm," Opt. Express 14, 1145-1160 (2005).
[CrossRef]

A. Proulx, J.-M., Ménard, N. Hô, J. M. Laniel, R. Vallée, and C. Paré, "Intensity and polarization dependences of the supercontinuum generation in birefringent and highly nonlinear microstructured fibers," Opt. Express 11, 3338-3345 (2003).
[CrossRef] [PubMed]

Z. Zhu and T. G. Brown, "Experimental studies of polarization properties of supercontinua generated in a birefringent photonic crystal fiber," Opt. Express 12, 791-796 (2004).
[CrossRef] [PubMed]

Opt. Lett. (9)

I. Hartl, X. D. Li, C. Chudoba, R. K. Ghanta, T. H. Ko, J. G. Fujimolo, J. K. Ranka, and R. S. Windeler, "Ultrahigh-resolution optical coherence tomography using continuum generation in an air silica microstructure optical fiber," Opt. Lett. 26, 608-610 (2001).
[CrossRef]

D. L. Marks, A. L. Oldenburg, J. J. Reynold, and S. A. Boppart, "Study of an ultrahigh-numerical-aperture fiber continuum generation source for optical coherence tomography," Opt. Lett. 27, 2010-2012 (2002).
[CrossRef]

B. Povazay, K. Bizheva, A. Unterhuber, B. Hermann, H. Sattmann, A. F. Fercher, W. Drexler, A. Apolonski, W. J. Wadsworth, J. C. Knight, P. S. J. Russell, M. Vetterlein, and E. Scherzer, "Submicrometer axial resolution optical coherence tomography," Opt. Lett. 27, 1800-1802 (2002).
[CrossRef]

K. Bizheva, B. Povazay, B. Hermann, H. Sattmann, W. Drexler, M. Mei, R. Holzwarth, T. Hoelzenbein, V. Wacheck, and H. Pehamberger, "Compact, broad-bandwidth fiber laser for sub-2- m m axial resolution optical coherence tomography in the 1300 nm wavelength region," Opt. Lett. 28, 707-709 (2003).
[CrossRef] [PubMed]

Y. Zaouter, J. Didierjean, F. Balembois, G. L. Leclin, F. Druon, P. Georges, J. Petit, P. Goldner, and B. Viana, "47-fs diode-pumped Yb3+:CaGdAlO4 laser," Opt. Lett. 31, 119-121 (2006).
[CrossRef] [PubMed]

J. R. Buckley, S. W. Clark, and F. W. Wise, "Generation of ten-cycle pulses from an ytterbium fiber laser with cubic phase-compensation," Opt. Lett. 31, 1340-1342 (2006).
[CrossRef] [PubMed]

B. E. Bouma, G. J. Tearney, I. P. Bilinsky, B. Golubovic, and J. G. Fujimoto, "Self-phase-modulated Kerr-lens mode-locked Cr:forsterite laser source for optical coherence tomography," Opt. Lett. 21, 1839-1841 (1996).
[CrossRef] [PubMed]

G. Boyer, "High-power femtosecond-pulse reshaping near the zero-dispersion wavelength of an optical fiber," Opt. Lett. 24, 945-947 (1999).
[CrossRef]

N. R. Newbury, B. R. Washburn, K. L. Corwin, and R. S. Windeler, "Noise amplification during supercontinuum generation in microstructure fiber," Opt. Lett. 28, 944-946 (2003).
[CrossRef] [PubMed]

Other (3)

H. Wang and A. M. Rollins, "Dual band supercontinuum light source for OCT," in Biomedical Optics 2006 Technical Digest (Optical Society of America, 2006), Tui30.

I. Hartl, A. M. Kowalevicz, P.-L. Hsiung, T. H. Ko, T. Schibli, F. X. Kärtner, J. G. Fujimoto, T. A. Birks, W. J. Wadsworth, U. Bünting, and D. Kopf, "Ultrahigh resolution optical coherence tomography using novel femtosecond laser sources," in Ultrafast Phenomena XIII, R. D. Miller, M. M. Murnane, N.F. Scherer, and A. M. Weiner, eds. (Springer-Verlag, 2003), pp. 660-662.

G. P. Agrawal, Nonlinear Fiber Optics (Academic, 2001).

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Figures (12)

Fig. 1
Fig. 1

Dispersion profile of the photonic crystal fiber (NL-1050-ZERO-2) used in this work. Two ZDWs are shown at 990 and 1123 nm . The inset is a scanning electronic micrograph of NL-1050-ZERO-2 used to calculate the dispersion profile.

Fig. 2
Fig. 2

Continuum generated (a) experimentally and (b) numerically with different lengths of NL-1050-ZERO-2 PCF. The continuum spectrum is relatively smooth when the PCF is less than 0.7 m, but the sidebands are fully extended only after 1.2 m. Significant modulations can be observed on the two sidebands after 1.2 m of PCF.

Fig. 3
Fig. 3

Smoothing of the spectrum of continuum at (a) 1300 nm and (b) 830 nm with polarization control. The dashed curve is the spectrum of the pump laser.

Fig. 4
Fig. 4

PSF of the smoothed continuum at 830 and 1300 nm by polarization control.

Fig. 5
Fig. 5

Suppression of the PSF sidelobes attributable to modulation on the 1300 nm band and the 830 nm band using linear polarization control; best case (dashed curve), worst case (solid curve).

Fig. 6
Fig. 6

(a) OCT image of a human fingernail bed in vivo at 1300 nm . The top surfaces are a glass slide and transparent gel. [ 740 ( h ) × 1000 ( v ) pixels, 6 mm ( h ) × 1.5 mm ( v ) ] (b) OCT image of a mouse ear in vivo at 830 nm . The thickness of a mouse ear is between 300 and 400 μm . [ 800 ( h ) × 750 ( v ) pixels, 4 mm ( h ) × 0.6 mm ( v ) ].

Fig. 7
Fig. 7

Simulated spectrum development as pulse propagates in the PCF. Dashed curves show the two ZDWs.

Fig. 8
Fig. 8

Numerically simulated continuum generated in 1.2 m of NL-1050-ZERO-2 PCF. (a) Includes only Kerr effect (SPM and DFWM); (b) Kerr and Raman effects are included. The contribution of SRS to spectral modulation is apparent in (b). The two peaks at 936 and 978 nm in (a) are separated by approximately 13.2 THz.

Fig. 9
Fig. 9

(a) Simulated spectrum, and (b) spectrum experimentally generated with polarization control by pumping 0.2 m PCF with 45 fs pulse and 40 mw average power in the PCF.

Fig. 10
Fig. 10

(a) Spectrum generated in 0.3 m SC980 and (b) autocorrelation trace of short pulse generated by prism compression.

Fig. 11
Fig. 11

PSFs measured with a free-space interferometer with the spectrum optimized by polarization control.

Fig. 12
Fig. 12

(a) OCT image of human colon in vitro at 830 nm with axial resolution of 2.8 μm in tissue [ 1500 ( h ) × 3500 ( v ) pixels, 5 mm ( h ) × 2.4 mm ( v ) ] (b) OCT image of human colon in vitro at 1300 nm with axial resolution of 4.5 μm in the tissue [ 1500 ( h ) × 3500 ( v ) pixels, 5 mm ( h ) × 2.4 mm ( v ) ]. (c) OCT image of the same tissue and using the same interferometer as used in (b), but using a common SLED light source at 1310 nm with axial resolution of 11 μm in the tissue.

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