Imlau M, Brüning H, Schoke B, Hardt R-S, Conradi D, Merschjann C
Department of Physics, University of Osnabrück, Barbarastr 7, 49069 Osnabrück, Germany.
Opt Express. 2011 Aug 1;19(16):15322-38. doi: 10.1364/OE.19.015322.
Hologram recording is studied in thermally reduced, nominally undoped lithium niobate in the time domain from 10 ns to 100 s by means of intense ns pump laser pulses (λ = 532 nm) and continuous-wave probe light (λ = 785 nm). It is shown that mixed absorption and phase gratings can be recorded within 8 ns that feature diffraction efficiencies up to 23 % with non-exponential relaxation and lifetimes in the ms-regime. The results are explained comprehensively in the frame of the optical generation of a spatial density modulation of Nb(Li)(4+/5+) antisites and the related optical features, i.e. absorption as well as index changes mutually related via the Kramers-Kronig-relation. Implications of our findings, such as the electrooptical properties of small bound Nb(Li)(4+) polarons, the optical features of Nb(Li)(4+):Nb(Nb)(4+) bipolarons, Nb(Nb)(4+) free polarons and O-hole-polarons, the impact of light polarization of pump and probe beams as well as of the polaron density are discussed.
通过强纳秒泵浦激光脉冲（λ = 532 nm）和连续波探测光（λ = 785 nm），在时域从10纳秒到100秒对热还原的、名义上未掺杂的铌酸锂中的全息记录进行了研究。结果表明，在8纳秒内可以记录混合吸收和相位光栅，其衍射效率高达23%，具有非指数弛豫且寿命在毫秒量级。在Nb(Li)(4+/5+)反位的空间密度调制的光生框架以及相关光学特性（即通过克拉默斯 - 克朗尼格关系相互关联的吸收和折射率变化）内，对这些结果进行了全面解释。讨论了我们研究结果的影响，例如小束缚Nb(Li)(4+)极化子的电光特性、Nb(Li)(4+):Nb(Nb)(4+)双极化子、Nb(Nb)(4+)自由极化子和O空穴极化子的光学特性、泵浦光和探测光的光极化以及极化子密度的影响。
