Nobuo Nishimiya

Saturated absorption spectroscopy of Xe using a GaAs semiconductor laser

Doppler-free absorption spectrum from 5P(5)6S to 5P(5)6P transitions of Xe in a hollow cathode discharge was measured in the wavelength region from 810 to 910 mn. The saturated dip signals detected by a frequency modulated probe beam were doubly AM-modulated by a pump beam chopped using a conventional mechanical chopper. The Doppler background was greatly reduced by detection using a second lock in amplifier synchronous to the chopping signal. The isotope shifts of even mass (136-128)Xe in natural abundance were resolved for the five transitions from the metastable states of J = 2 and 0, while in the transitions from the J = 1 states were partially resolved. The nuclear magnetic and quadrupole hyperfine coupling constants of 131Xe and 129Xe determined are listed with those reported previously. The specific mass shifts and the field shifts were estimated using the relation given by Kings diagram and compared with those obtained from the changes in the mean square-radii of the nuclear charge distribution.

Doppler-Free Two-Photon Spectroscopy of 6S1=2-6D3=2;5=2 Transition in Cesium

The Doppler-free two-photon spectra of the 6 S 1/2 ( F = 3)–6 D 3/2 ( F = 2 to 5), 6 S 1/2 ( F = 4)–6 D 3/2 ( F = 2 to 5), 6 S 1/2 ( F = 3)–6 D 5/2 ( F = 5 to 1) and 6 S 1/2 ( F = 4)–6 D 5/2 ( F = 6 to 2) transitions in cesium are observed using a titanium-sapphire laser. These spectra can be used as an optical frequency standard. The hyperfine coupling constants A (magnetic dipole constant) and B (electric quadrupole constant) are determined using spectral line splittings, giving A = 16.17(17) MHz and B = 0.11(127) MHz for the 6 D 3/2 state, and A =-4.56(9) MHz and B = -0.35(183) MHz for the 6 D 5/2 state.

Frequency measuring system using mirror gap stabilized Fabry-Perot interferometer.

The mirror gap of a Fabry-Perot interferometer was stabilized with two laser diodes; one locked to the line frequency 385,243,555.14445 MHz of the F=3<--1 in 5D(3/2)<--5S(1/2) (87Rb) and the other to the 385,284,566.3663 MHz of the F=4<--2 in 5D(5/2)<--5S(1/2) (87Rb) [Opt. Commun. 102 (1993) 432]. The length of the mirror gap was adjusted to generate the zero-cross points simultaneously at both of the two line positions. The fringe signals obtained from an interferometer thus stabilized can be used as frequency markers having accuracies of the order of 10(10) depending on the finesse of the interferometer used. Based on measurement using Cs D1 hyperfine lines reported by Udem et al. [Phys. Rev. Lett. 82 (1999) 3568], the uncertainty of markers in the region 50 THz apart from the reference lines is +/- 5 MHz.

Isotope shift of Ti spectrum in a facing target sputtering system

E cyclotron resonance heating (ECRH) in nuclear fusion devices such as tokomaks and stellarators, owing to overdense plasma is inefficient. This inefficiency is due to reflections of the waves at the so-called wave cut-offs. A two-step linear conversion process from ordinary mode (O mode) into extraordinary mode (X mode) and finally to slow electrostatic electron Bernstein wave (EBW), (OXB), can overcome this inefficiency and eliminate any density limits. In this article, we examine the transmission coefficient of O-X mode conversion for the optimal and density fluctuated launch conditions with parameters corresponding to the Wendelstein 7-X (W7-X) stellarators.At the dawn of the 21st century, the solid‐state analogue of the interaction between atom and light in a superconducting circuit was theoretically proposed by Yu. Makhilin, G. Schon, and A. Shnirman [Rev. Mod. Phys. 73, 357 (2001)] and by F. Marquardt and C. Bruder [Phys. Rev. B63, 054514 (2001) ] . It has been experimentally demonstrated by I. Chiorescu, et al. [Nature 431, 159 (2004)] and by A. Wallraff, et al. [Nature 431, 162 (2004)]. In that solid‐state analogue, an artificial atom and a microwave are used respectively for the atom and the light. The artificial atom is made by using a superconducting LC circuit. The harmonic oscillator atom is obtained in the case without any Josephson junction as in Fig.l(a), and the 2‐ıevel atom is based on the anharmonicity coming from Josephson junctions as in Fig. 1(b). QuantizingS specific DNA mutations determine whether programmed DNA rearrangements diversify antigen receptor loci genes. However, patients with various malignancies demonstrate DNA mutagenesis skewed toward the sense strand genome wide. Using single-molecule super-resolution microscopy, we have identified sub nuclear compartments in B cells where biologically programmed strand-specific DNA mutagenesis are engineered at focal DNA/RNA hybrid structures. The strand specific distribution of DNA mutations is determined by the coupled activities of two RNA helicases, Mtr4 and Senataxin, along with the noncoding RNA processing function of RNA exosome. Our study envisions that the regulatory mechanism of strand specific DNA mutagenesis in sub nuclear compartments during programmed and aberrant DNA mutagenesis events will play a major role in other undiscovered aspects of organismic development.

Zeeman spectra of Ti I in a facing target sputtering system

E cyclotron resonance heating (ECRH) in nuclear fusion devices such as tokomaks and stellarators, owing to overdense plasma is inefficient. This inefficiency is due to reflections of the waves at the so-called wave cut-offs. A two-step linear conversion process from ordinary mode (O mode) into extraordinary mode (X mode) and finally to slow electrostatic electron Bernstein wave (EBW), (OXB), can overcome this inefficiency and eliminate any density limits. In this article, we examine the transmission coefficient of O-X mode conversion for the optimal and density fluctuated launch conditions with parameters corresponding to the Wendelstein 7-X (W7-X) stellarators.At the dawn of the 21st century, the solid‐state analogue of the interaction between atom and light in a superconducting circuit was theoretically proposed by Yu. Makhilin, G. Schon, and A. Shnirman [Rev. Mod. Phys. 73, 357 (2001)] and by F. Marquardt and C. Bruder [Phys. Rev. B63, 054514 (2001) ] . It has been experimentally demonstrated by I. Chiorescu, et al. [Nature 431, 159 (2004)] and by A. Wallraff, et al. [Nature 431, 162 (2004)]. In that solid‐state analogue, an artificial atom and a microwave are used respectively for the atom and the light. The artificial atom is made by using a superconducting LC circuit. The harmonic oscillator atom is obtained in the case without any Josephson junction as in Fig.l(a), and the 2‐ıevel atom is based on the anharmonicity coming from Josephson junctions as in Fig. 1(b). QuantizingS specific DNA mutations determine whether programmed DNA rearrangements diversify antigen receptor loci genes. However, patients with various malignancies demonstrate DNA mutagenesis skewed toward the sense strand genome wide. Using single-molecule super-resolution microscopy, we have identified sub nuclear compartments in B cells where biologically programmed strand-specific DNA mutagenesis are engineered at focal DNA/RNA hybrid structures. The strand specific distribution of DNA mutations is determined by the coupled activities of two RNA helicases, Mtr4 and Senataxin, along with the noncoding RNA processing function of RNA exosome. Our study envisions that the regulatory mechanism of strand specific DNA mutagenesis in sub nuclear compartments during programmed and aberrant DNA mutagenesis events will play a major role in other undiscovered aspects of organismic development.

Optogalvanic double-resonance spectrum of Kr detected using frequency-modulated GaAs semiconductor lasers

State-selective optogalvanic spectroscopy has been performed using frequency-modulated GaAs semiconductor lasers. The first laser beam modulated by the sine wave of frequency f1 irradiated a laser galvatron filled with Kr of natural abundance and generated the signal corresponding to the 2p4-1s3 transition. The second one modulated by f2 was introduced along the first beam, which was frequency-locked to one of the hyperfine components of 83Kr. The intermodulated optogalvanic signal detected by a lock-in amplifier with the reference of f1+f2 was the second derivative and those by 2f1+f2 was the third derivative of the double-resonance line profile. The signals split by the nuclear hyperfine effect were clearly isolated from the strong signal of the even-mass Kr.