WEB High fidelity periodic poling of x-cut thin film lithium niobate for integrated optics analyzed with second harmonic microscopyTuesday (22.09.2020) 10:25 - 10:40 F: Functional Materials, Surfaces, and Devices 2 Part of:
Nonlinear optics in periodically-poled thin film lithium niobate (TFLN) promises superior performance and conversion efficiencies compared to their bulk counterparts. The keys to high nonlinear conversion efficiency are high fidelity periodic poling of waveguides with a homogenous domain duty cycle, and long poling length (at least for several mm). Recently observed conversion efficiencies are limited by poling length or by inhomogeneous domain duty cycles. In this work we demonstrate periodic poling of TFLN using a single poling pulse with a tailored waveform. The poling process is analyzed in detail with Second Harmonic (SH) microcopy which provides non-destructive information about the poling quality, such as the poling depth of inverted domains measured with a 10 nm depth resolution. This enables us to produce near-perfect poling of domains over the entire length of up to 5 mm with a periodicity as small as 3 µm. Such devices are shown to possess a high SH conversion efficiency, as well as high-quality and narrow-band entangled photon-pair generation at telecommunication wavelengths.