A few years ago in photorefractive crystals of LiTaO3:Cu (1) and LiNbO 3:Cu (2) a new nonlinear optic phenomenon, called the parametric scattering of 'holographic type', has been observed. As in the case of well-known (3) wide-angle species of photoinduced scattering, this process was degenerate. But it occurred under condition of phase-matching for four coupling waves: 2K sub L(omega)=K sub s1(omega) + K sub s2(omega) and hence had narrow spatial ...
Photoinduced charge transport in lithium niobates is defined by presence of a iron-like impurity, Fe(2+) being the donor, Fe(3+) - the acceptor of electrons. Two level scheme gives the linear dependence of photoconductivity (that is of inverse response times of photorefraction) on the light intensity. We discuss the influence of Me impurities (Me = Mg,Zn). provided for optical damage resistance in LiNbO3, on photoelectric phenomena. Me impurity affects photoconductivity of ...
Magnesium, zinc and some other impurities (substituting mainly for the lithium sites) drastically change optical properties of LiNbO3. In Particular the value of optical damage (photorefraction) in LiNbO:Me (me = Mg,Zn. is sharply reduced compared with undoped LiNbO3. Similarly Me impurities tend to suppress so-called dark trace effect (that means stable darkening under intensive visible laser radiation). The dependences of optical properties on Me concentrations demonstrate some common features. First ...
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