Hideaki Kano

We have developed ultrabroadband multiplex coherent anti-Stokes Raman scattering (CARS) microspectroscopy using a coherent supercontinuum in the near-infrared region generated from a photonic crystal fiber. Owing to the ultrabroadband Stokes radiation obtained from the supercontinuum, multiple vibrational modes can be excited simultaneously in the wave-number range of more than 2500cm−1. A CARS imaging of a lipid vesicle is demonstrated with a high vibrational contrast.

Dynamics of excited states in porphyrin J-aggregates has been investigated using femtosecond time-resolved fluorescence and absorption spectroscopies. An ultrafast relaxation process due to internal conversion (IC) from the S2-exciton state to the S1-exciton state is observed as an S2-fluorescence and a recovery from a bleaching of the S2-exciton state. The S2-fluorescence shows a sharp spectrum with almost no Stokes shift with a decay-time constant of 360±70 fs. In the transient absorption spec

Supercontinuum-based multiplex coherent anti-Stokes Raman scattering (CARS) microspectroscopy has been applied to vibrational imaging of a living fission yeast cell. We have successfully extracted only a vibrationally resonant CARS image from a characteristic spectral profile in the C-H stretching vibrational region. Using our simple but sensitive analysis, the vibrational contrast is significantly improved in comparison with a CARS imaging at a fixed Raman shift. The CARS image of a living yeas

Fast CARS: The cell-death process was observed in real time at the subcellular level by coherent anti-Stokes Raman microspectroscopy, an extension of anti-Stokes Raman scattering (CARS) microscopy. Changes in the chemical contrast during the dying process can be clearly resolved (see picture).

An interaction of the Frenkel exciton with the molecular vibration has been studied using sub-5-fs multichannel real-time spectroscopy. The coherent molecular vibration with a 135 ± 4 fs period is observed in the time-frequency two-dimensional difference absorption spectrum. An analysis of the phase and amplitude of the oscillation has revealed that both of the negative (bleaching and photoinduced emission) and positive (photoinduced absorption) signals are modulated synchronously. The experimen

Femtosecond time-resolved coherent anti-Stokes Raman scattering (CARS) spectroscopy is demonstrated using a Ti:Sapphire oscillator and a photonic crystal fiber. A spectrally dispersed CARS signal of cyclohexane exhibits well-defined beats with a period of 430fs, which agrees well with a frequency difference between the symmetric and antisymmetric CH2-stretching vibrational modes.

The temporal and spectral profiles of supercontinuum radiation generated from a photonic crystal fiber are evaluated with a polarization-gate frequency-resolved optical gating technique. The supercontinuum is then applied to coherent inverse Raman spectroscopy. A stimulated Raman signal of cyclohexane is observed as an induced absorption signal with an instantaneous response. The Raman signal has a peak at a slight negative delay time, which is explained by perturbed Raman-induced coherence.

A supercontinuum light source generated with a femtosecond Ti:Sapphire oscillator has been used to obtain both vibrational and two-photon excitation fluorescence (TPEF) images of a living cell simultaneously at different wavelengths. Owing to an ultrabroadband spectral profile of the supercontinuum, multiple vibrational resonances have been detected through coherent anti-Stokes Raman scattering (CARS) process. In addition to the multiplex CARS process, multiple electronic states can be excited d

Sub-5-fs spectroscopy of porphyrin J-aggregates reveals a coherent molecular vibration coupled to the Frenkel exciton. The bleaching and induced absorption signals show synchronous oscillations with the frequency of 244 cm-1. The coherent oscillation is explained by a modulated transition dipole moment, which is due to a dynamic intensity borrowing from the intense B-transition to the weak Q-transition through the ruffling mode with the 244 cm-1-frequency.

Abstract We have generated a dispersion‐compensated picosecond ultrabroadband supercontinuum light source at the sample position without using any additional compensator such as a prism pair or a grating pair. The dispersion‐compensated supercontinuum, which is obtained just by optimizing the length of a photonic crystal fiber, has been used as a Stokes laser source for ultrabroadband multiplex coherent anti‐Stokes Raman scattering (CARS) spectroscopy. Owing to an optimized temporal overlap betw

During cell division, various organelles behave dynamically. Visualization of these dynamic behaviors of organelles is a promising one step forward for understanding life at the molecular level. One- or two-photon excited fluorescence microscopy has so far been used for visualizing these cell dynamics. The fluorescent probe introduced into a living cell can visualize the spatial distribution of a target molecule in real time, enabling the tracing of cell dynamics at the molecular level. Introduc

ABSTRACT: Fermentation processes of bread doughs were traced by MRI (magnetic resonance imaging), which suggests that punching and rounding treatment after the first fermentation promotes the development of elasticity and extensibility of gluten fibrils that makes thin grain walls of the pores connecting between adjacent pores with small holes, and a thin smooth crust after baking. While pore generation was small, expansion of the dough was low, gluten networks formed were large and coarse, and

Coherent Raman scattering microscopy such as coherent anti‐Stokes Raman scattering and stimulated Raman scattering microscopy boosts the weak Raman signal and enables us to perform label‐free visualization of the molecular distribution and its dynamical behavior in living cells and tissues with high speed. In comparison with fluorescence imaging, cells and tissues can be visualized without specifying the target molecule. In this review, we describe the characteristics of a hyperspectral coherent

journal article

Despite growing demand for truly naïve imaging, label-free observation of cilium-related structure remains challenging, and validation of the pertinent molecules is correspondingly difficult. In this study, in retinas and cultured cells, we distinctively visualized Rootletin filaments in rootlets in the second harmonic generation (SHG) channel, integrated in custom coherent nonlinear optical microscopy (CNOM) with a simple, compact, and ultra-broadband supercontinuum light source. This SHG signa