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In silicon photonics, BaTiO3 (BTO) emerges as a promising electro‐optic (EO) integrated material due to its excellent EO modulation capabilities. Nevertheless, the EO response of multi‐domain BTO thin films tends to be lower than that of bulk materials. BTO thin films are fabricated with strong EO responses utilizing the pulsed laser deposition technique. Considering the importance of the SrTiO3 (STO) buffer layer, a series of epitaxial BTO thin films are deposited on STO substrates with engineered domain alignment. Given the contribution of domain variants in BTO thin films to their EO response, specific electrode patterns are designed to enhance their performance. An effective Pockels coefficient of 286 pm V−1 is determined for the BTO thin film via the transmission geometry method, which surpasses recent reports. Through domain engineering in the BTO thin film, the remarkable enhancement in the EO response arising from in‐plane polarization (a‐axis) characteristics is confirmed. Simultaneously, utilizing the Second Harmonic Generation (SHG) optical probe, deep exploration into the domain dynamics within BTO thin films is conducted. These findings provide insights into the contribution of domain variants to the EO response and shed light on further developing silicon‐based heterogeneously integrated devices. [ABSTRACT FROM AUTHOR]

Surface acoustic waves (SAWs) are used in a broad range including electronic systems and various sensors. Especially, SAW‐based microfluidic actuations at microscale represent an effective way with unrivaled precision and technological relevance. However, it remains a daunting challenge to develop a reliable and robust method for in situ and real time probing of the acoustic propagation of SAWs. Approach‐based sophisticated equipment claims large consumption and fussy operation, and is also limited for rapid analysis inside microfluidic channels. Other emerging methods suffer from limitations associated with the reproducibility or the application scenarios. Here, a convenient approach is achieved by interfacing with lanthanide emitters. The coupling between ferroelectric host and lanthanide ions promises effective emission manipulation upon external stimuli induced by the SAWs. The photoluminescence fluctuations of lanthanide emitters reflect their interaction with the strain and piezoelectric fields accompanying the propagating SAWs. The strong correlation between the lanthanide luminescence and the acoustic fields can visualize the resonant frequency, energy flow as well as propagation loss of the propagating SAWs on demand without degrading the SAW‐based functionality. These findings would accelerate the development of SAW‐based devices owing to the added functionality provided by the SAW‐luminescence correlative character. [ABSTRACT FROM AUTHOR]

Herein, a 20‐fold enhancement of the optical second harmonic generation (SHG) from WS2 monolayers by cooperating with SiO2 dielectric microspheres (MSs) is reported. Detailed experiment and simulation studies indicate that the SHG enhancement is dominantly originated by the enhanced excitation intensity and enlarged collection efficiency produced by the SiO2 MSs. The size effect of the SiO2 MS on the SHG enhancement is also systematically investigated. Moreover, the SHG enhancement is found to be very sensitive to the surrounding refractive index of the SiO2 MS, which advocates great promise for the photonic sensing applications. This work provides a low‐cost and efficient approach to enhancing the SHG emission, and demonstrates great potential for functional nanodevices based on hybrid dielectric structures. A 20‐fold enhancement of the optical second harmonic generation (SHG) from WS2 monolayers by cooperating with SiO2 dielectric microspheres (MSs) is reported. The SHG enhancement is attributed to the increased excitation intensity and enlarged collection efficiency produced by the SiO2 MSs. Moreover, a proof‐of‐concept photonic sensing application based on SHG is demonstrated. [ABSTRACT FROM AUTHOR]