A. M. Shegeda

The application of the weak magnetic field pulse to measure g-factors of ground and excited optical states by a photon echo method

A new scheme of the definition of g-factors as ground and excited optical states of a paramagnetic ion in zero external constant magnetic field has been proposed and experimentally realized in optical systems in which the Zeeman effect is manifested. A pulse of a weak magnetic field leads to the occurrence of relative phase shifts of the excited dipoles and, as a consequence, to modulation of a photon echo wave form if the magnetic pulse overlaps in time with the echo pulse. The modulation periods of the wave form depend on polarization of the laser light which excites the photon echo. The values of these periods for σ - and π-laser light polarization have been measured and then the g-factors of the ground 4I15/2 and excited 4F9/2 states of the Er3+ ion in the LuLiF4 and the YLiF4 matrices have been determined. The g-factor values have been compared with the known literary data.New scheme of definition of g-factors as ground as excited optical states of a paramagnetic ion in zero external constant magnetic field has been proposed and experimentally realized in optical systems in which Zeeman Effect is manifested. A pulse of a weak magnetic field leads to occurrence of relative phase shifts of the excited dipoles and, as consequence, to modulation of a photon echo waveform if magnetic pulse (MP) overlaps in time with echo-pulse. The modulation periods of the waveform depend on polarization of the laser light, which excites the photon echo. The values of these periods for {\sigma}- and {\pi}- laser light polarization have been measured and then the g-factors of the ground 4I15/2 and excited 4F9/2 states of the Er3+ ion in the LuLiF4 and the YLiF4 matrices have been determined. Values of the g-factors have been compared with the known literary data.

The application of weak electric field pulses to measure the pseudo-Stark split by photon echo beating

New scheme for determining the pseudo-Stark splitting of optical lines has been proposed and experimentally realized. A pulse of a weak electric field leads to occurrence of relative phase shifts of the excited dipoles and, as consequence, to beating of a photon echo wave form if electric pulse overlaps in time with echo-pulse. The value of the pseudo-stark splitting is the inverse period of the beats. The photon echo beating of the R1-line in Ruby have been observed. The pseudo-Stark splitting has been determined and it’s value have been compared with the known literary data. PACS numbers: 42.50.Md, 42.65.VhA novel scheme for determining the pseudo-Stark splitting of optical lines has been suggested and tested in experiment. The scheme allows one to observe the beating of a photon echo waveform under conditions of overlap in time between a weak electric pulse and its echo-pulse. The pseudo-Stark splitting is equal to the inverse average modulation period of the echo waveform. The photon echo beating of the R1-line in Ruby has been observed. The dependence of the inverse average modulation period of the echo waveform on the average value of the electric field over the optically excited volume has been found. The obtained values of the pseudo-Stark parameter are in good agreement with known literature data.

New possibilities of photon echo: determination of ground and excited states g-factors applying a weak magnetic field pulse

We have measured the magnetic parameters of a paramagnetic ion in the ground and excited states by controlling the relative phases of excited dipoles with pulse of a weak magnetic field. Er3+ in two crystals LuLiF4 and YLiF4 has been used as a paramagnetic ion. The second matrix was used for control. Optical transition is 4I15/2 → 4F9/2.

Multichannel information processing in the optical echo-processors on the basis of Van-Fleck paramagnet crystals

The analysis of various modes of multichannel information recording and readout in conditions of a stimulated (accumulated and long-living) photon echo in the crystals doped with rare earth ions which are known as Van-Fleck paramagnets has been performed in order to utilize them in the operation of low-temperature optical echo-processors.

Effect of the Excitation Radiation Coherence on Oscillations of the Photon Echo Intensity

The physical reasons for observing the splitting of optical lines several orders of magnitude smaller than the spectral width of a laser pulse are investigated. A theory of coherent and incoherent photon echo (PE) in an external static magnetic field and in the presence of a pulsed magnetic field, which causes oscillations of the PE intensity, is elaborated. It is shown that the periods of oscillations in the echo intensity, the echo duration, and the dimensions of the regions in the inhomogeneous line, where the excited ions are coherent, do not depend on the degree of coherence of the laser pulse and on the external static magnetic field. As follows from the theory, in the case of the coherent excitation of the echo, the amplitude of the intensity oscillations is independent of the external static magnetic field if the inhomogeneous line is symmetric. It is shown that the amplitude of the oscillations at the incoherent excitation of the echo is equal to the autocorrelation function of the distribution function of the transition frequency along the inhomogeneous line with the argument equal to the Zeeman splitting of the optical line in the external magnetic field. In this case, the experimental values of the oscillation amplitude are in good agreement with the calculated values of the autocorrelation function for the total inhomogeneous line in LuLiF4:Er3+ (4I15/2⇒F9/2 transition). In the same way, the autocorrelation function has been obtained for YLiF4:Er3+ on the same transition.

Optical superradiance in a Pr{sup 3+}:LaF{sub 3} crystal

Optical superradiance was experimentally obtained for the first time on the 3P0?3H4(0) transition in a Van Vleck paramagnet ? a Pr3+:LaF3 crystal. Superradiance at a wavelength of 477.7 nm was emitted by a sample 8 mm long, with resonant absorption coefficient ?=4.7 cm-1, excited by 10-ns laser pulses at a temperature of 2.2 K.