title: Fast spectral coherent anti-Stokes Raman scattering microscopy with high-speed tunable picosecond laser.
abstract: We develop a coherent anti-Stokes Raman scattering (CARS) microscopy system equipped with a tunable picosecond laser for high-speed wavelength scanning. An acousto-optic tunable filter (AOTF) is integrated in the laser cavity to enable wavelength scanning by varying the radio frequency waves applied to the AOTF crystal. An end mirror attached on a piezoelectric actuator and a pair of parallel plates driven by galvanometer motors are also introduced into the cavity to compensate for changes in the cavity length during wavelength scanning to allow synchronization with another picosecond laser. We demonstrate fast spectral imaging of 3T3-L1 adipocytes every 5  cm-1 in the Raman spectral region around 2850  cm-1 with an image acquisition time of 120 ms. We also demonstrate fast switching of Raman shifts between 2100 and 2850  cm-1, corresponding to CD2 symmetric stretching and CH2 symmetric stretching vibrations, respectively. The fast-switching CARS images reveal different locations of recrystallized deuterated and nondeuterated stearic acid.
authors.affiliation: Osaka University, Graduate School of Engineering Science, 1-3 Machikaneyama, Toyonaka-shi, Osaka 560-8531, Japan.
authors.forename: Harsono
authors.initials: H
authors.lastname: Cahyadi
authors.forename: Junichi
authors.initials: J
authors.lastname: Iwatsuka
authors.forename: Takeo
authors.initials: T
authors.lastname: Minamikawa
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Niioka
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Araki
authors.forename: Mamoru
authors.initials: M
authors.lastname: Hashimoto
mesh_terms: D017667:Adipocytes / Q000737:chemistry; D000818:Animals; D002460:Cell Line; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007834:Lasers; D008055:Lipids / Q000737:chemistry; D051379:Mice; D008853:Microscopy / Q000379:methods*; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D008055:Lipids