Electrical Properties of Tungstates Ln2(WO4)3 (Ln – Gd, Ho)

<p>Electrical properties of Gd₂(WO₄)₃ and Ho₂(WO₄)₃ were studied and the type of charge carriers was determined. The studied compounds have a salt-like isle structure with isolated tetrahedrons. It crystallises in the Еu₂(WO₄)₃ structural type, so-called ‘defective scheelite’, in which 1/3 of Ln sites are vacant, Ln_2/3[V_Ln]_1/3WO₄. Predominant ionic conductivity in Ln₂(WO₄)₃ (Ln = Gd, Ho) was established both by the EMF method and from independence of conductivity versus oxygen partial pressure. A minor contribution (4-11%) of the anion [WO₄]^2- transport was detected by the Tubandt method, which along with the results of the EMF technique proves the predominant oxygen conductivity.</p>

Applying Non-Steady-State Photo-Emf Technique to Detection of Higher Order Auto Correlation Functions of Ultrashort Optical Pulses

Here we examine a new application of the adaptive detectors based on non-steady-state photo-electro-motive force effect for the detection of higher order correlation functions, aiming the estimation of the parameters of ultra short optical pulses arranged in high-repetition trains. For this purpose three beam interferometer scheme with two signal beams modulated at different frequencies is proposed. Theoretical analysis of non-steady-state photo-EMF current generated by light distribution formed by superposition of three waves is performed and the possibility to detect simultaneously second and higher order correlation function is demonstrated. Potential advantages and disadvantages of such detection scheme for measuring the higher order auto-correlations functions are discussed.