2013 Conference on Lasers and Electro-Optics Pacific Rim (CLEOPR), 2013
ABSTRACT We generate second-harmonic Er-fiber laser pulses with suppressed intensity noise by col... more ABSTRACT We generate second-harmonic Er-fiber laser pulses with suppressed intensity noise by collinear balanced detection technique, and Yb fiber laser pulses with a wide tunability (~250 cm-1) to demonstrate fiber-laser-based stimulated Raman microspectroscopy of polymer beads.
Cleo Qels 2010 Laser Science to Photonic Applications, 2010
ABSTRACT Long ring-cavity, all-polarization maintaining, Er-doped fiber laser using single wall c... more ABSTRACT Long ring-cavity, all-polarization maintaining, Er-doped fiber laser using single wall carbon nanotube polyimide film was demonstrated. Output pulses with pulse energy of 0.7∼2.6 nJ were obtained at ultra low repetition rate of 943∼154 kHz.
The first experiment of time-resolved spectral imaging of liquid in laser ablation is reported. A... more The first experiment of time-resolved spectral imaging of liquid in laser ablation is reported. An interferometric spectral imaging system dedicated to the measurements of the laser ablation is constructed. A pair of two-dimensional arrays of images are formed by a lenslet array coupled with a polarization interferometer and superposed on a detection plane. Each image in the array is provided with a varied path difference by the wedge-shaped liquid-crystal polarization interferometer to generate the interference signals. These interference signals include all the information necessary to reconstruct a spectral image and can be collected simultaneously. The mechanism of ablation of phenanthrene/ethanol solution was investigated by making use of the time-resolved spectral images of the laser induced plume. The results suggest that the photothermal processes are dominant in the ablation of the solution.
Journal of the Optical Society of America B Optical Physics, 2010
A high-speed, high-resolution, and large-scanning-range three-dimensional measurement system was ... more A high-speed, high-resolution, and large-scanning-range three-dimensional measurement system was demonstrated using an electronically controlled wavelength-tunable orthogonally polarized high-power ultrashort twin pulse source and an all-fiber interferometer. Thanks to the high peak power, the ultrashort optical pulses propagated along a fiber while maintaining the pulse shape by means of the soliton effect, allowing us to demonstrate high-speed, high-resolution, and large-scanning-range measurement. First, the interference was analyzed by numerical calculations and then the measurement system was demonstrated experimentally. A longitudinal scanning range of about 25 mm, a longitudinal resolution of 33 m, and a scanning speed of 1000 points/s were achieved without moving parts. For a measurement distance of 0.5 m, a sensitivity of 60 dB was obtained. Clear three-dimensional images of a 100 yen Japanese coin and metal samples were obtained using this system.
We obtained a temporal and permanent refractive index change in niobium tellurite glasses by usin... more We obtained a temporal and permanent refractive index change in niobium tellurite glasses by using ps-and fs-pulses, respectively. A He-Ne laser beam was guided by a line waveguide structure drawn by the fs-pulses, indicating positive refractive index change. It is suggested that the refractive index change by the ps-pulses is due to an increase in the absorption coefficient while that caused by the fs-pulses results from the rearrangement of the glass structure.
2013 Conference on Lasers and Electro-Optics Pacific Rim (CLEOPR), 2013
ABSTRACT We generate second-harmonic Er-fiber laser pulses with suppressed intensity noise by col... more ABSTRACT We generate second-harmonic Er-fiber laser pulses with suppressed intensity noise by collinear balanced detection technique, and Yb fiber laser pulses with a wide tunability (~250 cm-1) to demonstrate fiber-laser-based stimulated Raman microspectroscopy of polymer beads.
Cleo Qels 2010 Laser Science to Photonic Applications, 2010
ABSTRACT Long ring-cavity, all-polarization maintaining, Er-doped fiber laser using single wall c... more ABSTRACT Long ring-cavity, all-polarization maintaining, Er-doped fiber laser using single wall carbon nanotube polyimide film was demonstrated. Output pulses with pulse energy of 0.7∼2.6 nJ were obtained at ultra low repetition rate of 943∼154 kHz.
The first experiment of time-resolved spectral imaging of liquid in laser ablation is reported. A... more The first experiment of time-resolved spectral imaging of liquid in laser ablation is reported. An interferometric spectral imaging system dedicated to the measurements of the laser ablation is constructed. A pair of two-dimensional arrays of images are formed by a lenslet array coupled with a polarization interferometer and superposed on a detection plane. Each image in the array is provided with a varied path difference by the wedge-shaped liquid-crystal polarization interferometer to generate the interference signals. These interference signals include all the information necessary to reconstruct a spectral image and can be collected simultaneously. The mechanism of ablation of phenanthrene/ethanol solution was investigated by making use of the time-resolved spectral images of the laser induced plume. The results suggest that the photothermal processes are dominant in the ablation of the solution.
Journal of the Optical Society of America B Optical Physics, 2010
A high-speed, high-resolution, and large-scanning-range three-dimensional measurement system was ... more A high-speed, high-resolution, and large-scanning-range three-dimensional measurement system was demonstrated using an electronically controlled wavelength-tunable orthogonally polarized high-power ultrashort twin pulse source and an all-fiber interferometer. Thanks to the high peak power, the ultrashort optical pulses propagated along a fiber while maintaining the pulse shape by means of the soliton effect, allowing us to demonstrate high-speed, high-resolution, and large-scanning-range measurement. First, the interference was analyzed by numerical calculations and then the measurement system was demonstrated experimentally. A longitudinal scanning range of about 25 mm, a longitudinal resolution of 33 m, and a scanning speed of 1000 points/s were achieved without moving parts. For a measurement distance of 0.5 m, a sensitivity of 60 dB was obtained. Clear three-dimensional images of a 100 yen Japanese coin and metal samples were obtained using this system.
We obtained a temporal and permanent refractive index change in niobium tellurite glasses by usin... more We obtained a temporal and permanent refractive index change in niobium tellurite glasses by using ps-and fs-pulses, respectively. A He-Ne laser beam was guided by a line waveguide structure drawn by the fs-pulses, indicating positive refractive index change. It is suggested that the refractive index change by the ps-pulses is due to an increase in the absorption coefficient while that caused by the fs-pulses results from the rearrangement of the glass structure.
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Papers by Kazuyoshi Itoh