In life science, rapid mutation detection in oligonucleotides is in a great demand for genomic and medical screening. To satisfy this demand, surface-enhanced resonance Raman spectroscopy (SERRS) in the deep-UV (DUV) regime offers a promising solution due to its merits of label-free nature, strong electromagnetic confinement, and charge transfer effect. Here, we demonstrate an epitaxial aluminum (Al) DUV-SERRS substrate that resonates effectively with the incident Raman laser and the ss-DNA at 266 nm, yielding significant SERRS signals of the detected analytes. For the first time, to the best of our knowledge, we obtaine SERRS spectra for all bases of oligonucleotides, not only revealing maximum characteristic Raman peaks but also recording the highest enhancement factor of up to 106 for a 1 nm thick adenine monomer. Moreover, our epitaxial Al DUV-SERRS substrate is able to enhance the Raman signal of all four bases of 12-mer ss-DNA and to further linearly quantify the single-base mutation in the 12-mer ss-DNA.

Electromagnetic components are important for ultraviolet (UV) applications. However, due to the limitation in the materials’ intrinsic responses, there are fewer electromagnetic components in high-frequency regimes than in low-frequency ones. Conventional UV components manipulate the wavefront via geometric phase accumulation; thus, they are significantly bulky and inefficient. In this study, we demonstrate all-dielectric Huygens’ metasurface (ADHMS) at a near-ultraviolet (NUV) regime. The NUV-ADHMS is comprised of resonant titanium dioxide (TiO2) nanodisks, with the ultrathin thickness of the fifth wavelength. In addition, by modulating the diameter of the resonant TiO2 nanodisks, we can simultaneously excite and control both electric and magnetic dipoles, achieving a powerful wavefront engineering of the near-unity transmittance and a full range of the 2π phase coverage. Finally, we employed the NUV-ADHMS to bend a normal incident beam, demonstrating a deflection angle of 11° at a wavelength of 405 nm.

Plasmonics has been demonstrated to improve the performance of various optoelectronic devices operating in the infrared to visible wavelength regime. However, limited by optical properties of suitable plasmonic materials in ultraviolet (UV) regimes, rare works have been devoted to UV applications with plasmonic structures. This work deliberately fabricates a heterogeneous array of Al nanocaps (Al‐NC) on a wide‐bandgap semiconductor of GaN truncated nanocones (GaN‐TNC) and then presents a multifunctional plasmonic sensor for excellent UV photodetection and air‐quality‐index (AQI) gas sensing. As a UV photodetector, this work shows maximum responsivity (1.8 × 108 AW−1) and detectivity (1.2 × 1018 Jones) at the resonance wavelength of 355 nm, which based on the current knowledge, is the highest detectivity among GaN‐based UV photodetectors. Such a UV photodetector also introduces a decent response of rise time (78.3 ms) and fall time (303.5 ms), respectively. As a gas sensor, this work detects a key AQI gas of NO2 and provides a superior response of 28% and a detection limit of 500 ppb, respectively.