Takasi Endo

Violation of the optical bloch equations in power broadening of an impurity-ion solid, ruby

Abstract Power broadening (PB) of the optical holes for the transition (-1/2) 4 A 2 ↔(-1/2)Ē( 2 E) in ruby R 1 line was studied in the magnetic field (0.5 k0e) along the c -axis. It was found that the PB was much narrower than that expected from the optical Bloch equations. A qualitative interpretation based on a nonstochastic model is given.

Coherent Raman beats associated with superhyperfine structure in ruby

Abstract Coherent Raman beats associated with superhyperfine structure (shfs) due to Cr-Al interaction were observed in ruby. The rf modulated Stark field was used to create coherences between shfs sublevels under the irradiation with a cw ruby laser. From the beat frequencies high resolution spectra of shfs with width (HWHM) of about 10 kHz were obtained in the frequency range from about 4.5 to 6.5 MHz. The utility of phase sensitive detection technique combined with rf Stark modulation was demonstrated. The observed spectra were compared with the theoretical ones.

Narrow optical hole burning and related effects in ruby

Abstract We observed a narrow optical hole burning in ruby whose width (FWHM = 107 kHz) is the narrowest of those reported so far in solids. A hole before reaching its steady state which we call transient hole was used on the basis of theoretical analysis of the hole burning. The first observation of optical wiggles and the detection of superhyperfine structures near zero frequency are reported as two new effects related to the narrow optical hole burning.

Studies of phase characteristics of various photon echoes with a phase sensitive detection method

Abstract Various optical coherent transient signals in ruby have been examined by using an optical phase sensitive detection (PSD) technique. The PSD is performed by comparing the phase of the heterodyne beat signals obtained by the Stark switching technique with that of a local oscillator whose frequency is equal to the heterodyne beat frequency. The optical FID, two-pulse photon echoes, radiation locked echoes and notched echoes have been detected as υ-mode signals with small u -mode signals probably due to the asymmetry of the inhomogeneous broadening. The dependence of the phase of the radiation locked and notched echoes upon the driving pulses is also examined. The experimental results are in good agreement with theoretical predictions based on Bloch equations.

Experimental verification of oscillatory free induction decay

Abstract Oscillatory behavior in the free induction decay, predicted by Schenzle, Wong and Brewer, was observed and examined quantitatively for the first time by using inhomogeneously broadened proton nuclear magnetic resonance.

Frequency-locking of a CW dye laser to some absorption lines of a neon discharge by a Faraday filter

Abstract Single-mode oscillations of a CW dye laser at the center of five absorption lines from the 1s states to the 2p states of neon were obtained by means of a neon discharge Faraday filter, without any other frequency-selective elements. The most striking thing observed is that saturated absorption takes place at the center of several absorption lines in a Faraday filter, in addition to optical rotation.

Optical adiabatic rapid passage by linear frequency chirping in ruby

Abstract The population inversion by optical adiabatic rapid passage (ARP) has been observed, for the first time, in a solid, ruby, under a linear frequency chirping using Stark effect. In addition to the emission after ARP, the phase-inverted optical free induction decay(fid) signals indicating population inversion were observed and used to measure the degree of population inversion precisely. The experimental results were compared with Horwitzs calculation and numerical solutions of Bloch equations with relaxation terms. The decay of the population inversion was also measured.

Absence of spectral diffusion in a dilute ruby

Abstract Spectral diffusion in a dilute (0.0034 wt%) ruby in high magnetic fields (∥ c axis) was examined by monitoring the time evolution of a narrow optical hole (width ≈0.8 MHz). It was found that the spectral diffusion due to spin flips of the neighboring Al nuclei is absent or these nuclei form a frozen core.

Oscillatory optical free induction decay and photon echoes

Abstract Oscillatory behaviors of FID and two-pulse echoes, which are expected when the inhomogeneous broadening is large compared with the homogeneous one and the pulse area is larger than 2π, have been observed for the first time in the optical region. The experiment was carried out on ruby by using Stark switching technique. The radiation-locked type photon echoes were examined. Experimental results were compared with theoretical calculations based on Bloch equations.

Ballistic Quantum Walk in a Discrete One-Dimensional System

A continuous-time quantum walk in a one-dimensional discrete system is considered. There are interactions \(\hbar v/\Delta x\) between adjacent sites, where Δ x denotes the lattice spacing. If the initial state is spread over N sites, the packet travels ballistically with velocity v for N ≫1.