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Abstract Pyroelectric detectors are often broadband and require external filters for wavelength‐specific applications. This paper reports a tunable, narrowband, and lightweight pyroelectric infrared detector built upon a flexible membrane of As2S3−Ag−P(VDF‐TrFE) with subwavelength grating, which is capable of both on‐chip filtering and photopyroelectric energy conversion. The top surface of this hybrid membrane is a corrugated As2S3−Ag film contributing to narrowband light absorption in the near‐infrared (NIR) regime, and the bottom part is a polyvinylidene fluoride‐trifluoroethylene (PVDF‐TrFE) membrane for the conversion of the absorbed light to an electrical signal. Uniquely, applying a bias voltage to the PVDF‐TrFE membrane enables the tuning of the device's absorption and pyroelectric characteristics owing to the piezoelectrically induced mechanical bending. The resonator exhibited a resonant absorption coefficient of 80% and a full‐width‐half‐maximum of 15 nm within the NIR, a responsivity of 1.4 mV mW−1, and an equivalent noise power of 13 µW Hz−1/2at 1560 nm. By applying a 15‐V bias to the PVDF‐TrFE membrane, the absorption coefficient decreased to 18% due to the change in the grating period and incident angle. The narrowband and tunable features of the As2S3−Ag−P(VDF‐TrFE) pyroelectric detector will benefit a variety of potential applications in sensors, optical spectroscopy, and imaging.
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Abstract Nucleic acid tests have been widely used for diagnosis of diseases by detecting the relevant genetic markers that are usually amplified using polymerase chain reaction (PCR). This work reports the use of a plasmonic device as an efficient and low‐cost PCR thermocycler to facilitate nucleic acid‐based diagnosis. The thermoplasmonic device, consisting of a one‐dimensional metal grating, exploited the strong light absorption of plasmonic resonance modes to heat up PCR reagents using a near‐infrared laser source. The plasmonic device also integrated a thin‐film thermocouple on the metal grating to monitor the sample temperature. The plasmonic thermocycler is capable of performing a PCR amplification cycle in ~2.5 minutes. We successfully demonstrated the multiplex and real‐time PCR amplifications of the antibiotic resistance genes using the genomic DNAs extracted from
Acinetobacter baumannii ,Klebsiella pneumonia ,Escherichia coli andCampylobacter . -
Abstract Here, a wavelength‐specific photo‐thermoelectric (PTE) device is reported that achieves narrowband optical absorption and thermoelectric conversion functions using a stack of thin films on a grating‐patterned substrate. Conventional PTE devices are broadband with the absorption of electromagnetic radiation from ultraviolet to terahertz. There are demands for PTE devices that can exhibit narrowband response at a desired wavelength. Here, the narrowband PTE device consists of a photonic crystal (PC) filter with metal cladding and a thin‐film thermocouple. The PC‐PTE design is investigated numerically to illustrate the underlying energy conversion mechanism. The device is fabricated using nanoreplica molding followed by coating of thin films. The fabricated metal‐cladding PC resonator exhibits a narrowband optical absorption with a resonant absorption coefficient of 85.4% and full‐width‐half‐maximum of 14.8 nm in the visible wavelength range. The PTE measurements show that the thermoelectric output is sensitive to the coupling of incident light and guided‐mode resonance modes. Illuminated under the resonant condition, the PTE device exhibits a responsivity and noise equivalent power of 0.26 V W−1and 7.5 nW Hz−1/2, respectively. This PC‐PTE technology has the unique attributes of narrowband detection, large surface area, and low cost for the potential application in sensors, optical spectroscopy, and imaging.