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Contents of talk: 1. Ferroelectric materials and domains2. Domain manipulation (poling)3. Light assisted poling (LAP)4. All optical poling (AOP) Regular periodic arrays v. random self-organisation.5. Latent poling:6. Mechanisms and conclusions

Ferroelectric materials such as lithium niobate (LN) or lithium tantalate (LT) are examples of an extremely versatile class of optical crystals. In bulk single crystal, single domain format, these crystalline hosts find numerous applications in nonlinear optics, optical storage, photorefraction, surface acoustic wave devices, optical waveguides, piezoelectric and pyroelectric devices and electro-optic modulation. Single domain crystals can be subsequently engineered via spatially selective poling to yield domain structures whose size can lie in the region of a few tens of µm to sub-µm, for applications and device fabrication that are impossible to implement in single domain geometry. This paper discusses our progress to date in micro- and nanostructuring of such materials, for applications in nonlinear optics, switching and deflection, and 3-dimensional sculpting for possible MEMS use, The techniques and benefits are discussed of using both light-assisted and direct optical poling for achieving controllable domains that can be irregular or periodic, bulk or surface, at sizes that approach the 100 nm scale. For surface inversion, domain features can be produced that lack the otherwise characteristic crystal symmetry imposed hexagonal shapes observed in conventional electric field poling.

A simpler, alternative to 'prism type' electro-optic (EO) solid state deflectors has been recently demonstrated. This device is essentially a single interface version of a conventional deflector, but significant deflection is achieved by setting the input beam at grazing incidence to the interface (where, additionally, it can act as an EO switch). The increased deflection seen near TIR is, however, made at the expense of increased divergence of the output beam. Overall deflection can be a misleading quantity to determine the performance of a deflector as this could always be increased with suitable lenses. A more reliable figure of merit is the number of separate resolvable spots that can be imaged from the deflector output. Here we analyze the achievable resolution for a single interface deflector. It can be seen that with a suitably sized device, significant resolution can be attained from a single interface deflector as shown in Fig.1. The resolution is shown here as a function of temperature since if the deflector were to be working at visible wavelengths if would necessarily be heated to avoid photo-refractive effects. Additionally heating has a secondary role in increasing resolution due to the intrinsic n term in the EO equation. Although there are still issues to overcome in terms of the output beam quality of a single interface deflector, it does possess one major advantage over the previous, multiple interface deflectors. Due to its simplicity it can be fashioned to function in 2 dimensions (Fig.2). This would be the first ever report to our knowledge of a 2D EO solid state beam deflector.