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Masaru Hori - One of the best experts on this subject based on the ideXlab platform.

  • measurement of hydrogen radical density and its impact on reduction of copper oxide in atmospheric pressure remote plasma using h2 and ar mixture gases
    Applied Physics Express, 2010
    Co-Authors: Hirotoshi Inui, Keigo Takeda, Hiroki Kondo, Kenji Ishikawa, Makoto Sekine, Hiroyuki Kano, Naofumi Yoshida, Masaru Hori
    Abstract:

    A 60 Hz alternating current excited atmospheric-pressure plasma with an ultrahigh electron density of over 1016 cm-3 employing H2/Ar [ p(H2)/p(H2+Ar) 1–3%] gases was used to reduce copper oxides on copper. The remote plasma reduced CuO and Cu2O at room temperature. The ground-state hydrogen (H) radical density in the atmospheric-pressure plasma was measured by vacuum ultraviolet absorption spectroscopy using a micro hollow cathode Lamp. The ratio of reduction of amount of CuO flux to the H radical flux was determined from the measured H radical density and gas temperature.

  • Surface Loss Probability of Nitrogen Atom on Stainless-Steel in N2 Plasma Afterglow
    Japanese Journal of Applied Physics, 2010
    Co-Authors: Seigo Takashima, Keigo Takeda, Mineo Hiramatsu, Satoshi Kato, Masaru Hori
    Abstract:

    We investigated the loss kinetics of nitrogen (N) atoms in a N2 plasma afterglow using a vacuum ultraviolet absorption spectroscopy technique with an atmospheric-pressure microdischarge hollow cathode Lamp. The decay curves of N atom density were fitted with single exponential functions at pressures from 1.33 to 13.3 Pa. The dependence of the decay time constant on the pressure showed that the N atoms were predominantly lost through diffusion to the wall surface. The surface loss probability of N atoms on stainless-steel based on the decay time constant as a function of pressure was estimated to be 0.03.

  • Vacuum ultraviolet absorption spectroscopy employing a microdiacharge Hollow-Cathode Lamp for absolute density measurements of hydrogen atoms in reactive plasmas
    Applied Physics Letters, 1999
    Co-Authors: Seigou Takashima, Akihiro Kono, Masaru Hori, Toshio Goto, Masafumi Ito, Katsumi Yoneda
    Abstract:

    We have developed a measurement technique for absolute H-atom densities in process plasmas using vacuum ultraviolet absorption spectroscopy employing a high-pressure microdischarge Hollow-Cathode Lamp (MHCL) as a Lyman α (Lα, 121.6 nm) emission light source. Characterization of the Lα emission-line profile could be simplified by using a high-pressure discharge at about 1 atm. The effect of self-absorption in the MHCL was reduced to an insignificant level by decreasing the H2 partial pressure. The contribution of the collisional broadening to the Lα emission profile was estimated from the saturation characteristics of the absorption intensity when the optical thickness of the plasma was varied. The technique was applied to the measurement of the absolute H-atom density in an inductively coupled H2 plasma.

  • Measurement of Carbon Atom Density in High Density Plasma Process
    Japanese Journal of Applied Physics, 1997
    Co-Authors: Masanobu Ikeda, Takashi Takeo, Hajime Hattori, Masaru Hori, Toshio Goto
    Abstract:

    Carbon atom densities in an inductively coupled radio frequency (13.56 MHz) CO and CO and H2 mixed plasmas were successfully measured for the first time using ultra-violet absorption spectroscopy (UVAS) with a carbon hollow cathode Lamp. This method, developed for monitoring carbon atoms in-situ in the plasmas, is very useful for the investigation of etching and chemical vapor deposition (CVD) processes containing carbon atoms and the sputtering system employing a carbon target.

Katsumi Yoneda - One of the best experts on this subject based on the ideXlab platform.

  • Vacuum ultraviolet absorption spectroscopy employing a microdiacharge Hollow-Cathode Lamp for absolute density measurements of hydrogen atoms in reactive plasmas
    Applied Physics Letters, 1999
    Co-Authors: Seigou Takashima, Akihiro Kono, Masaru Hori, Toshio Goto, Masafumi Ito, Katsumi Yoneda
    Abstract:

    We have developed a measurement technique for absolute H-atom densities in process plasmas using vacuum ultraviolet absorption spectroscopy employing a high-pressure microdischarge Hollow-Cathode Lamp (MHCL) as a Lyman α (Lα, 121.6 nm) emission light source. Characterization of the Lα emission-line profile could be simplified by using a high-pressure discharge at about 1 atm. The effect of self-absorption in the MHCL was reduced to an insignificant level by decreasing the H2 partial pressure. The contribution of the collisional broadening to the Lα emission profile was estimated from the saturation characteristics of the absorption intensity when the optical thickness of the plasma was varied. The technique was applied to the measurement of the absolute H-atom density in an inductively coupled H2 plasma.

Seigou Takashima - One of the best experts on this subject based on the ideXlab platform.

  • Vacuum ultraviolet absorption spectroscopy employing a microdiacharge Hollow-Cathode Lamp for absolute density measurements of hydrogen atoms in reactive plasmas
    Applied Physics Letters, 1999
    Co-Authors: Seigou Takashima, Akihiro Kono, Masaru Hori, Toshio Goto, Masafumi Ito, Katsumi Yoneda
    Abstract:

    We have developed a measurement technique for absolute H-atom densities in process plasmas using vacuum ultraviolet absorption spectroscopy employing a high-pressure microdischarge Hollow-Cathode Lamp (MHCL) as a Lyman α (Lα, 121.6 nm) emission light source. Characterization of the Lα emission-line profile could be simplified by using a high-pressure discharge at about 1 atm. The effect of self-absorption in the MHCL was reduced to an insignificant level by decreasing the H2 partial pressure. The contribution of the collisional broadening to the Lα emission profile was estimated from the saturation characteristics of the absorption intensity when the optical thickness of the plasma was varied. The technique was applied to the measurement of the absolute H-atom density in an inductively coupled H2 plasma.

Yoshio Torii - One of the best experts on this subject based on the ideXlab platform.

  • doppler free spectroscopy of metastable sr atoms using a hollow cathode Lamp
    Applied Optics, 2018
    Co-Authors: Yusuke Hayakawa, Takatoshi Aoki, Takumi Sato, Chika Watanabe, Yoshio Torii
    Abstract:

    We report on the demonstration of Doppler-free spectroscopy of metastable Sr atoms using a hollow cathode Lamp (HCL). We employed a custom Sr HCL, which is filled with a mixture of 0.5 Torr Ne and 0.5 Torr Xe as a buffer gas to suppress velocity changing collisions and increase the populations in all of the (5s5p)3PJ(J=0,1,2) metastable states. We performed frequency modulation spectroscopy for the (5s5p)3P0−(5s6s)3S1, (5s5p)3P1−(5s6s)3S1, (5s5p)3P2−(5s5d)3D2, and (5s5p)3P2−(5s5d)3D3 transitions with sufficient signal-to-noise ratios for laser frequency stabilization. We also observed the hyperfine transitions of (5s5p)3P2−(5s5d)3D3 of Sr87. This method would greatly facilitate laser cooling of Sr.

  • A simplified 461-nm laser system using blue laser diodes and a hollow cathode Lamp for laser cooling of Sr
    Review of Scientific Instruments, 2013
    Co-Authors: Yosuke Shimada, Yuko Chida, Nozomi Ohtsubo, M. Takeuchi, Takahiro Kuga, Takatoshi Aoki, Yoshio Torii
    Abstract:

    We develop a simplified light source at 461 nm for laser cooling of Sr without frequency-doubling crystals but with blue laser diodes. An anti-reflection coated blue laser diode in an external cavity (Littrow) configuration provides an output power of 40 mW at 461 nm. Another blue laser diode is used to amplify the laser power up to 110 mW by injection locking. For frequency stabilization, we demonstrate modulation-free polarization spectroscopy of Sr in a hollow cathode Lamp. The simplification of the laser system achieved in this work is of great importance for the construction of transportable optical lattice clocks.

  • A 461 nm Laser System and Hollow-Cathode Lamp Spectroscopy for Magneto-Optical Trapping of Sr Atoms
    Journal of the Physical Society of Japan, 2012
    Co-Authors: Takatoshi Aoki, Kotaro Umezawa, Yuki Yamanaka, Naotomo Takemura, Yasuhiro Sakemi, Yoshio Torii
    Abstract:

    We develop a laser system with a wavelength of 461 nm and a power of 175 mW using a master oscillation power amplifier (MOPA) system and second-harmonic generation (SHG) via a KNbO3 crystal. To stabilize the laser frequency to the atomic absorption line, we measured the saturated absorption spectrum of a Sr Hollow-Cathode Lamp. The dependences of the Lamb dip signal and the frequency modulation spectrum on the pump beam power were observed. The collision broadening due to the Ne buffer gas increased the observed width of the signals in addition to the saturation effect. In spite of such an increased width (� 100 MHz), we demonstrated stable magneto-optical trapping of Sr atoms. The number of atoms obtained, 1 � 10 7 , is sufficient to proceed to various ultracold Sr atoms experiments.

Toshio Goto - One of the best experts on this subject based on the ideXlab platform.

  • Vacuum ultraviolet absorption spectroscopy employing a microdiacharge Hollow-Cathode Lamp for absolute density measurements of hydrogen atoms in reactive plasmas
    Applied Physics Letters, 1999
    Co-Authors: Seigou Takashima, Akihiro Kono, Masaru Hori, Toshio Goto, Masafumi Ito, Katsumi Yoneda
    Abstract:

    We have developed a measurement technique for absolute H-atom densities in process plasmas using vacuum ultraviolet absorption spectroscopy employing a high-pressure microdischarge Hollow-Cathode Lamp (MHCL) as a Lyman α (Lα, 121.6 nm) emission light source. Characterization of the Lα emission-line profile could be simplified by using a high-pressure discharge at about 1 atm. The effect of self-absorption in the MHCL was reduced to an insignificant level by decreasing the H2 partial pressure. The contribution of the collisional broadening to the Lα emission profile was estimated from the saturation characteristics of the absorption intensity when the optical thickness of the plasma was varied. The technique was applied to the measurement of the absolute H-atom density in an inductively coupled H2 plasma.

  • Measurement of Carbon Atom Density in High Density Plasma Process
    Japanese Journal of Applied Physics, 1997
    Co-Authors: Masanobu Ikeda, Takashi Takeo, Hajime Hattori, Masaru Hori, Toshio Goto
    Abstract:

    Carbon atom densities in an inductively coupled radio frequency (13.56 MHz) CO and CO and H2 mixed plasmas were successfully measured for the first time using ultra-violet absorption spectroscopy (UVAS) with a carbon hollow cathode Lamp. This method, developed for monitoring carbon atoms in-situ in the plasmas, is very useful for the investigation of etching and chemical vapor deposition (CVD) processes containing carbon atoms and the sputtering system employing a carbon target.