2015

Y. Kabessa, A. Yativ, H. Ilan, and A. J. Agranat, “Electro-Optical Modulation with Immunity to Optical Damage by Bipolar Operation in Potassium Lithium Tantalate Niobate,” Optics express , vol. 23, no. 4, pp. 4348-4356, 2015.Abstract
A method for suppressing the formation of optical damage in quadratic electrooptic devices operated at short wavelengths is presented. Formation of optical damage is attributed to the generation of a trapped space charge induced by photoionization of impurity ions by the propagating beam. It is shown that in potassium lithium tantalate niobate where the electrooptic effect is quadratic, operating the electrooptic device by a bipolar driving voltage prevents the space charge from accumulating, which inhibits the formation of the optical damage. A 6 hours continuous operation of electrooptic modulator for a 30 W/cm2 at λ = 445 nm input beam is demonstrated.
A. B. Yashar, H. Ilan, and A. J. Agranat, “Construction of waveguiding structures in potassium lithium tantalate niobate crystals by combined laser ablation and ion implantation,” App. Phys. A-Mat. Sci. & Process, vol. 118, no. 2, pp. 403-407, 2015. Publisher's VersionAbstract
A generic methodology for constructing complex integrated electro-optic circuits in waveguided configurations is presented. The method is based on combining two techniques, 'laser ablation' and 'refractive index engineering by ion implantations.' The constructed circuits are side-cladded by air trenches that were produced using laser ablation and bottom-cladded by a layer with a reduced refractive index which is generated through the implantation of He.sup.+ ions. This fabrication technique enables the construction of circular structures with complex geometry featuring small radii of curvature, and further can be employed to construct microfluidic channels on the same substrate. The research demonstrates waveguides in both linear and circular configurations that were constructed in a potassium lithium tantalate niobate (KLTN) substrate using the aforementioned method, proving that this substrate is a suitable candidate for use in creating laboratories-on-a-chip with multifunctional capabilities. The proposed techniques used in the research are generic and applicable to a wide range of substrates.