Optical wave propagation in double-periodic, quasi-periodic and disturbed optical lattices

双周期、准周期和扰动光学晶格中的光波传播

• 批准号: 35900073
• 负责人: Professor Dr. Detlef Kip
• 金额: --
• 依托单位: Fachgebiet Experimentalphysik und Materialwissenschaften
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/35900073?language=en
• 关键词: Optical; wave; propagation; double; periodic

The investigation of wave propagation in superlattices and distorted single-period lattices has been so far merely theoretical, although this is - due to universal properties - of fundamental interest and related to many physical systems. The main reasons for this situation are the still challenging technologies for model sample fabrication, a difficult but necessary almost full control of the wave and lattice properties, and a non-desired nonlinear interaction of waves with the lattice itself in most systems investigated so far.In this proposal, we plan to investigate experimentally optical wave propagation in one-dimensional optical superlattices and distorted single-period lattices. Fabrication of optical lattices will be performed using lithium niobate crystals, where one can achieve a full control of (super-) lattice periods, coupling constants, and magnitude of an optional nonlinearity. For the case of superlattices within this project, these may be either commensurate or incommensurate. By adequate sample fabrication different types of distortions in single-period lattices can be obtained externally by holographic recording in photorefractive lithium niobate. Furthermore, wave propagation can be easily controlled to be either linear or nonlinear. With the experimental techniques developed recently in our group, we are able to directly measure full 1D band structures including gaps and propagation constants of solitary states within a gap, and to directly observe excited states (either extended Floquet-Bloch modes, nonlinear extended modes, and localized states). Taking these prerequisites into account, by using this model system of wave propagation in periodic potentials, we will investigate physical situations in between the two limiting cases of purely periodic lattices where all states are extended, and completely random lattices where any state is localized.

波在超晶格和畸变单周期晶格中传播的研究目前还只是理论上的，尽管由于普适性质，这是一个基本的兴趣，并且与许多物理系统有关。造成这种情况的主要原因是仍然具有挑战性的技术模型样品的制造，一个困难的，但必要的几乎完全控制的波和晶格的属性，和一个非期望的非线性相互作用的波与晶格本身在大多数系统的调查迄今为止，在这个建议中，我们计划在实验上研究光波在一维光学超晶格和扭曲的单周期晶格的传播。光学晶格的制造将使用锂酸盐晶体进行，其中可以实现对（超）晶格周期、耦合常数和可选非线性的大小的完全控制。对于这个项目中的超晶格，它们可能是公度的或不公度的。通过适当的样品制作，可以在光折变晶体锂晶体中通过全息记录在外部获得单周期晶格中不同类型的畸变。此外，波的传播可以很容易地控制为线性或非线性。利用我们小组最近开发的实验技术，我们能够直接测量包括带隙和带隙内孤立态的传播常数在内的全一维能带结构，并直接观察激发态（扩展Floquet-Bloch模，非线性扩展模和局域态）。考虑到这些先决条件，通过使用这个模型系统的波传播的周期性的潜力，我们将调查的物理情况之间的两个极限情况的纯周期性的晶格中的所有状态的扩展，和完全随机的晶格中的任何状态是本地化的。