ACS Photonics最新文献

Power splitters are fundamental components for optical signal routing in photonic integrated circuits (PICs). Conventional power splitters, such as Y-branches, directional couplers, and multimode interferometers rely on nonresonant waveguiding effects, like index matching, mode coupling, and interference, which limit their design freedom for arbitrary and multiport light splitting in ultracompact footprints. Recent advancements in dielectric metasurfaces have opened new possibilities for compact on-chip devices. Here, based on Huygens’ meta-waveguides, we numerically and experimentally demonstrate efficient 1 × N (N = 2,3,4) power splitting in ultracompact footprints with low insertion loss. Particularly for 1 × 2 splitters, arbitrary power splitting can be realized by adjusting the relative positions of Huygens’ resonators without requiring full structural reoptimization. These designs utilize efficient light manipulation through nanoantennas and have potential for large-scale PICs, including applications in optical computing.

At room temperature, high-κ HfLaO is adopted as the gate dielectric to fabricate amorphous InGaZnO (a-IGZO) optical synaptic thin-film transistors (TFTs), for which plasma treatments are conducted on the HfLaO dielectric in O₂ and a-IGZO in Ar, respectively, namely, OPT/APT-TFTs. Consequently, high-performance a-IGZO TFTs are obtained with a high carrier mobility of 20.8 cm²/V·s, a high I_on/I_off ratio of 3.2 × 10⁶, and a small subthreshold swing (SS) of 0.25 V/dec. As compared to the pristine TFTs, the photocurrent of the OPT/APT-TFTs under a 365 nm ultraviolet (UV) light is significantly raised three times up to 1.4 μA. Meanwhile, the current decay percentage after irradiation removal is reduced from 98% down to 36% within 60 s, indicating an enhanced persistent-photoconductivity (PPC) effect. Accordingly, various optical synaptic plasticities are obtained based on which a simulated neuronal network with a high 93.22% accuracy is achieved to recognize MNIST handwritten digits. Moreover, both neurotransmitter and neuromodulator behaviors are concurrently emulated in a single device through exploiting the native three-terminal structure of the TFT. Importantly, an artificial visual nervous system is successfully constructed by integrating the a-IGZO optoelectronic TFTs for image recognition.

This study investigates the photoelectric performance of MoS₂-based field-effect transistors (FETs) integrated with a thin-film lithium niobate (TFLN) waveguide platform. The MoS₂ FET demonstrates high photodetection capabilities across a broad wavelength range from visible to near-infrared (up to 1550 nm). By adjusting the gate voltage from 0 V to −25 V, the dark current is reduced by over 6 orders of magnitude, reaching approximately 2 pA. Under 635 nm illumination, the device achieves a maximum responsivity of 940 A/W (at an input power of 35 pW), an on/off ratio (I_light/I_dark) of 10⁵, and a detectivity of 6.27 × 10¹⁴ W^–1. Significant photoresponse is also observed at telecommunication wavelengths with a responsivity of 68.7 mA/W and a detectivity of 4.58 × 10¹⁰ W^–1 at 1310 nm. Additionally, the response times is measured to be under 300 μs across all tested wavelengths. The combination of two-dimensional material FET and TFLN offers an attractive platform for realizing high-performance optoelectronic devices and multifunctional integrated photonic circuits.