Tadashi Aoki

Impulsive Optic-Acoustic Effect of CO2, SF6 and NH3 Molecules

A rapid change of pressure of gas is observed by using a condenser microphone when a CO2 laser pulse is incident on the various kinds of gases such as CO2, SF6 and NH3 in an absorption cell. By analysing a wave form of the pressure change, the relaxation times of vibration-translation interaction of the relevant levels of molecules are obtained. Acoustic waves are also generated by the laser pulse and superimposed with the above mentioned pressure wave. It is found that a polarity of the acoustic wave of CO2 is inverted from those of SF6 and NH3.

Enhanced spin-dependent parity-nonconservation effect in the

Employing the relativistic coupled-cluster method, comparative studies of the parity nonconserving electric dipole amplitudes for the

7s ^2S_{ 1/2} \to 6d ^2 D_{5/2}

7s\phantom{\rule{4pt}{0ex}}^{2}S_{1/2}\ensuremath{\rightarrow}6d\phantom{\rule{4pt}{0ex}}^{2}D_{5/2}

transition in Fr: A possibility for unambiguous detection of the nuclear anapole moment

transitions in

Efficient photon correlator for measuring transient waveforms of very weak fluorescence

^{210}\mathrm{Fr}

Photon statistics and autocorrelation of a multi-mode laser

and

Change of Discharge Current in CO2 Plasma Induced by Q-switched CO2 Laser

^{211}\mathrm{Fr}

Acoustic Waves Excited by Q-Switched CO2 Laser

isotopes have been carried out. It is found that these transition amplitudes, sensitive only to the nuclear spin-dependent effects, are enhanced substantially owing to the very large contributions from the electron core-polarization effects in Fr. This translates to a relatively large and, in principle, measurable induced light shift, which would be a signature of nuclear spin-dependent parity nonconservation that is dominated by the nuclear anapole moment in a heavy atom like Fr. A plausible scheme to measure this quantity using the Cyclotron and Radioisotope Center (CYRIC) facility at Tohoku University has been outlined.

Wide-dynamic-range digital correlator using field programmable gate arrays

An efficient photon correlator has been developed for the measurements of the temporal change of a very weak fluorescence. It was designed by using a TTL integrated circuit which is standard and easily available. Data acquired by an electric circuit were processed and accumulated in the memory of a computer. The system operates in a delayed counting mode and its temporal resolution is 25 ns.

Observation of negative third-order intensity cumulants in multimode lasers

Abstract The intensity fluctuation properties were experimentally studied for one mode among many oscillating longitudinal modes of an argon ion laser in a region sufficiently above threshold. The individual longitudinal mode fluctuated considerably even well above the threshold, while the laser intensity summed over all the longitudinal modes was observed stable. This fluctuation was found to be much larger than expected from the previous theoretical work by Arecchi and Ricca which did not consider the combination-tone polarization. The slowing-down and the increase of the fluctuation were observed when the excitation was lowered toward to its threshold value. The correlation time of the intensity fluctuation measured ranged from 0.7 μs to 20 μs depending on the oscillation condition.