2005 年分子構造総合討論会奨励賞受賞記念 解説記事

1 Mol. Sci. 1, A0005 (2007) MOLECULAR SCIENCE Award Accounts 2005 .. Coherent Raman Spectroscopy Using a Supercontinuum Light Source a Hideaki Kano Ultrabroad supercontinuum is generated when ultrashort laser pulses are injected into a photonic crystal fiber (PCF). Owing to the low threshold for the supercontinuum generation, the experimental setups have been significantly simplified by PCFs. We have applied the PCF-based supercontinuum light source to develop unique coherent Raman spectrometers. In the present paper, I would introduce two coherent anti-Stokes Raman scattering (CARS) systems, namely femtosecond CARS spectroscopy and ultrabroadband multiplex CARS microspectroscopy, both of which require only a single Ti:sapphire oscillator as a laser source.

2 The former allows us to investigate vibrational dynamics in real time, while the latter provides molecular specific multi-color images for biological samples with high speed. In particular, we have successfully visualized the mitosis process of living fission yeast cells at the molecular level. Keywords: supercontinuum, photonic crystal fiber, PCF, Raman spectroscopy, nonlinear Raman spectroscopy, coherent Raman spectroscopy, coherent anti-Stokes Raman scattering, CARS, multiplex CARS, microscopy, microspectroscopy, vibrational imaging, molecular imaging, pollen grain, living cell, yeast cell 1.

3 7 . SC PCF . SC . Supercontinuum; . SC 8 . 1(a) PCF PCF . SC 1969 . Alfano Shapiro 1, 2 . SC PCF . 1 Microstructured fiber . SC Holey fiber .. Photonic PCF . 3-5 6. crystal fiber; PCF SC PCF .. SC MW .. PCF kW . SC . SC .. SC . 350 nm 3000 nm SC Figure 1. (a) Cross section of a photonic crystal fiber. This is obtained by a Crystal Fibre A/S and NKT Research ( ); (b). 113-0033 7-3-1 Far-field beam pattern of supercontinuum. Japan Society for Molecular Science Page 1 of 8. (page number not for citation purpose). Mol. Sci. 1, A0005 (2007) Award Accounts CARS . PCF 1, 2 1, 2. PCF . PCF 1 2 . SC.

4 1(b) . SC . 1. SC . 9, 10. CARS . 11. SC 2(b) . 12. Optical Coherence Tomography; OCT . 13-15 16-23.. SC . SC . SC . 14. SC . CARS 30 . 2. CARS . CARS SC CARS .. SC. Coherent Anti-Stokes Raman Scattering; CARS CARS .. 24. Leonhardt 3 CARS . CARS . 25-29. CARS Coherent ; Vitesse PCF. 2(a) CARS Crystal Fiber ; SC .. 1 SC . 2 . Figure 2. (a) Energy diagram for coherent anti-Stokes Raman scattering (CARS) process; (b) Time ordering of the pump, Stokes, and Figure 3. Experimental setup for fs-CARS spectroscopy; BS: beam probe pulses. Gradation in the Stokes ( 2) pulse indicates temporal splitter; filter1: long-pass filter; filter2: short-pass filter; PMT: chirp; (c) Energy diagram for the nonresonant background.

5 Photomultiplier tube. Page 2 of 8. (page number not for citation purpose). Mol. Sci. 1, A0005 (2007) Award Accounts . CARS (Acton ; SpectraPro 300i) .. CARS . SC . SC . 2(b) . 1 2 . 1 . Figure 5. (a) Delay-time dependence of the fs-CARS signal of cyclohexane (red) and fitted result (blue); (b) Difference of the 4 CARS experimental and fitted results shown in (a); (c) Fourier-power spectrum of the oscillating component in the positive delay time in (b);.. (d) Spontaneous Raman spectrum of cyclohexane. 800 nm nm . C-H 430 fs . 4 1 2 CARS . CARS . 1 = 2 . I ( 1 ) = A ( 1 ) + B exp 2 1 T av G ( 1 ) (1).

6 1 = 0 2 = 0 2 . 5(a) 2 = 0 CARS . ( 1 ), G ( 1 ), , A, B, T av . 1 2. 230 fs .. T av . 2(c) 2. 4 5(a).. 5(b) .. 5(c) 75 cm-1.. 5(d) CH2 . SC. CARS .. CARS .. SC . CARS . SC CARS .. Figure 4. Two-dimensional intensity plot of fs-CARS signal. The sample is cyclohexane containing in a 1-mm thick cell. Delay1 and Delay 2 correspond to 1 and 2, respectively. Page 3 of 8. (page number not for citation purpose). Mol. Sci. 1, A0005 (2007) Award Accounts 3. CARS . CARS . CARS . 6 CARS . CARS . 31, 32 1 2 .. 33 1 2 .. in . situ 33-49 1 2 .. 1 . 36-39.. CARS . 1 . CARS 1 2 .. 1 CARS. 55, 67, 68 .. 1 m < 600cm-1.

7 SC 17, 18, 69, 70 SC . 50, 51. CARS CARS CARS . > 2800 cm-1 70, 71 .. 7 . CARS 18 . 52. CARS 1982 Coherent ; Vitesse . CARS PCF Crystal Fiber ; NL-PM-750 . 16, 53-66. SC SC . CARS 2 . CARS . Figure 6. Energy diagram for a multiplex CARS process. A. narrow-band pump (red) and broad-band Stokes (gray) laser pulses drive multiple vibrational coherences simultaneously. The vibrational coherences are probed by the pump pulse, giving rise to a multiplex CARS signal (orange). Figure 7. Experimental setup for multiplex CARS microspectroscopy. Page 4 of 8. (page number not for citation purpose). Mol.

8 Sci. 1, A0005 (2007) Award Accounts . 1 ( 20 cm-1) CARS .. CARS . CARS CARS . SC . NA 8 74 . CARS . CARS 75, 76 CARS . (Acton ; SpectraPro 300i) . CCD Roper Scientific ; Spec-10:400BR/XTE 100 ms . PIXIS 100B 8(a) CARS . MadCity; Nano-LP-100 1100, 1500 cm-1 .. CARS C-C, C=C 2850 cm-1. C-H .. C-H .. 72. m, m C-H . CARS . C-C, C=C . CARS C-H . 8(b-d). 2(c) C-C C=C C-H CARS . 8(b) (c) . 2(c) 2 1 . C-C C=C .. C-H CARS. 8(d) 8(b) (c) . 73.. CARS .. 2. AR R. I ( ) = ANR e i + i( ). R R R. (2). I ( ) ANR. AR . CARS R R .. Figure 8. (a) CARS spectrum of a pollen grain of flowering cherry;. CARS image of a pollen grain at the C-C (b), C=C (c), and C-H (d).

9 CARS stretching vibrational modes. Page 5 of 8. (page number not for citation purpose). Mol. Sci. 1, A0005 (2007) Award Accounts .. C-H .. CARS SC .. 77 . SC . CARS .. PCF. 9 Schizosaccharomyces pombe; S. pombe Crystal fibre . C-H CARS .. (No. 15GS0204) . B(No. 15750005, 18750007) .. CARS . (1) Alfano, R. R.; Shapiro, S. L. Phys. Rev. Lett. 1970, 24, 592-594.. (2) Alfano, R. R. The supercontinuum Laser Source;.. Springer-Verlag: Berlin, 1989. (3) Russell, P. Science 2003, 299, 358-362. 4. (4) Dudley, J. M.; Genty, G.; Coen, S. Rev. Mod. Phys. 2006, 78, PCF 1135-1184. SC (5) Bjarklev, A.; Broeng, J; Bjarklev, A.

10 S. Photonic Crystal Fibres;. SC Kluwer Academic Publishers: Dordrecht, 2003. (6) Ranka, J. K.; Windeler, R. S.; Stentz, A. J. Opt. Lett. 2000, 25, . 25-27. (7) Omenetto, F. G.; Wolchover, N. A.; Wehner, M. R.; Ross, M.;. Efimov, A.; Taylor, A. J.; Kumar, V. V. R. K.; George, A. K.;. Knight, J. C.; Joly, N. Y.; Russell, P. S. J. Opt. Express 2006, 14, 4928-4934. (8) Birks, T. A.; Wadsworth, W. J.; Russell, P. S. J. Opt. Lett. 2000, 25, 1415-1417. (9) Husakou, A. V.; Herrmann, J. J. Opt. Soc. Am. B 2002, 19, 2171-2182. (10) Herrmann, J.; Griebner, U.; Zhavoronkov, N.; Husakou, A.;. Nickel, D.