T. Yabuzaki

Frequency stabilization of GaAlAs laser using a Doppler-free spectrum of the Cs-D 2 line

Experimental results are shown on the frequency stabilization of a GaAlAs laser using a Doppler-free spectrum in the saturated absorption of the Cs-D 2 line at 852.1 nm. The frequency stability (Allan variance) between 3.0 \times 10^{-12} and 1.0 \times 10^{11} was obtained at the averaging time between 0.1 and 1000 s.

Frequency-Locking of a GaAlAs Laser to a Doppler-Free Spectrum of the Cs-D2 Line

Preliminary results are reported on the first frequency-locking of a cw GaAlAs laser, operating at room temperature on a single mode, to a Doppler-free spectrum in the saturated absorption of the Cs-D2 line at 852.1 nm.

Laser‐production of NaH crystalline particles

Production of NaH crystalline particles of μm size is observed in sodium vapor mixed with ∼10 Torr H2. The particles are produced when Na2 is excited to the B 1Πu state by a cw Ar+ laser, and also when Na is excited by a cw dye laser tuned to the D1 or D2 line.

Observation of Lorentz-group Berry phases in polarization optics

Abstract It is shown that Berrys phase for the Lorentz group can be observed in polarization optics. It appears as the rotation of the polarization plane of linearly polarized light which is passed through an array of linear polarizers. An experiment has been carried out to demonstrate the effect. The phenomenon is closely related to the phase shift due to a cycle of squeezings of light which is predicted by Chiao and Jordan. Connections with Pancharatnams phase is also discussed.

Frequency-locking of a CW dye laser to the center of the sodium D lines by a Faraday filter

Single-mode CW oscillations at the center of the sodium D lines have been achieved by inserting a Faraday filter in an argon-laser-pumped dye laser cavity. The oscillations at the D 1 and D 2 lines can be selected by choosing adequate values of the sodium temperature and the magnetic field strength. Experimentally obtained conditions to get the single-mode oscillations at the center of the D lines are compared with the theoretically calculated feature of the Faraday filter, and a relatively good agreement has been found. The shifts of oscillation frequencies due to the magnetic field are also discussed.

Frequency Stabilization of Diode Laser Using External Cavity and Doppler-Free Atomic Spectra

We report on the frequency stabilization of a diode laser, in which the long- and short-term stabilities are simultaneously improved. We use an external cavity whose resonance frequency is locked to the center of a Doppler-free spectrum of the 85 Rb-D 2 line without direct laser frequency modulation. The obtained linewidth of the diode laser is less than 100 kHz and the long-term stability (trackability) estimated from the variation of the error signal is between 2×10 -12 and 2×10 -14 at the averaging time τ between 100 ms and 100 s. We also propose a conventional method of stabilization of the magnetic field at the Rb cell used for the frequency stabilization

High proton polarization in crystalline naphthalene by dynamic nuclear polarization with laser excitation at room temperature and liquid nitrogen temperature

Abstract We have successfully polarized protons in naphthalene doped with pentacene at room temperature and liquid nitrogen temperature. Pentacene molecules have been excited with a laser beam and protons have been polarized dynamically in the triplet state of pentacene. We have obtained a polarization of about 13% at liquid nitrogen temperature in a field of about 3 kG with an N2 laser of about 150 mW. We expect to obtain a polarization higher than 30% with another type of laser.

Optical properties of impurity atoms in pressurized superfluid helium

We report on the optical properties of alkali atoms (Cs and Rb) in the pressurized superfluid helium. We observed excitation and emission spectra at various pressures from the saturated vapor pressure to about 25 atm. The theoretical calculations on the basis of the atomic bubble model have also been worked out. The qualitative agreement between the theoretical and experimental results with respect to the peak shift, the linewidth, and their pressure dependence is achieved in the framework of the spherical atomic bubble model. TheD2 excitation spectra with the double peaks are interpreted qualitatively in terms of the Jahn-Teller effect, indicating the existence of the nontotally symmetrical density distribution of the surrounding helium atoms.

Sublevel spectroscopy of alkali atoms in superfluid helium

We report the results of optical pumping and optical detection of magnetic resonance of alkali atoms (Cs and Rb) in superfluid helium. The magnetic resonances between the ground-state Zeeman sublevels and hyperfine levels are observed through monitoring theD1 fluorescence by means of the optical-rf double resonance technique. Although the ground stateg values in superfluid helium are the same as in vacuum within the experimental error, the hyperfine constant of the ground state of the Cs atom in superfluid helium is found to be slightly larger than in vacuum. Coherent transient spectroscopy is also performed.

Optical magnetic-resonance imaging of laser-polarized Cs atoms

Optical magnetic-resonance imaging (MRI) is performed to observe a density distribution of the laser-polarized Cs atoms that diffuse in helium buffer gas at roughly room temperature. Spatial resolution of optical MRI and sensitivity of optical detection are discussed for gaseous atoms in a weak magnetic field. We propose a fast method of three-dimensional optical MRI with parallel processing of signals from a photodetector array, and we discuss its application to the spin-polarized noble gas.