Ultrafast and sensitive (noise equivalent power <1 nW Hz ^−1/2 ) light‐detection in the terahertz (THz) frequency range (0.1–10 THz) and at room‐temperature is key for applications such as time‐resolved THz spectroscopy of gases, complex molecules and cold samples, imaging, metrology, ultra‐high‐speed data communications, coherent control of quantum systems, quantum optics and for capturing snapshots of ultrafast dynamics, in materials and devices, at the nanoscale. Here, we report room‐temperature THz nano‐receivers exploiting antenna‐coupled graphene field effect transistors integrated with lithographically‐patterned high‐bandwidth (∼100 GHz) chips, operating with a combination of high speed (hundreds ps response time) and high sensitivity (noise equivalent power ≤120 pW Hz ^−1/2 ) at 3.4 THz. Remarkably, this is achieved with various antenna and transistor architectures (single‐gate, dual‐gate), whose operation frequency can be extended over the whole 0.1–10 THz range, thus paving the way for the design of ultrafast graphene arrays in the far infrared, opening concrete perspective for targeting the aforementioned applications.

We observed the coupling of graphene Dirac plasmons with different surfaces using scattering-type scanning near-field optical microscopy integrated into a mid-infrared synchrotron-based beamline. A systematic investigation of a graphene/hexagonal boron nitride (h-BN) heterostructure is carried out and compared with the well-known graphene/SiO₂ heterostructure. Broadband infrared scanning near-field optical microscopy imaging is able to distinguish between the graphene/h-BN and the graphene/SiO₂ heterostructure as well as differentiate between graphene stacks with different numbers of layers. Based on synchrotron infrared nanospectroscopy experiments, we observe a coupling of surface plasmons of graphene and phonon polaritons of h-BN (SPPP). An enhancement of the optical band at 817 cm⁻¹ is observed at graphene/h-BN heterostructures as a result of hybridization between graphene plasmons and longitudinal optical phonons of h-BN. Furthermore, longitudinal optical h-BN modes are preserved on suspended graphene regions (bubbles) where the graphene sheet is tens of nanometers away from the surface while the amplitude of transverse optical h-BN modes decrease.

We report the photoresponse of niobium diselenide (NbSe₂), a transition metal dichalcogenide which exhibits superconducting properties down to a single layer. Devices are built by using micromechanically cleaved 2–10 layers and tested under current bias using nano-optical mapping in the 350 mK–5 K range, where they are found to be superconducting. The superconducting state can be perturbed by absorption of light, resulting in a voltage signal when the devices are current biased. The response is found to be energy dependent, making the devices useful for applications requiring energy resolution, such as bolometry, spectroscopy, and infrared imaging.