Graphene detector spots single photons using heat, not electricity
Researchers have demonstrated a radically different way to detect individual photons by measuring tiny temperature spikes in graphene rather than electrical signals. The advance could enable imaging and sensing systems that work with infrared and microwave light—wavelengths conventional detectors struggle with—opening applications from quantum networks to thermal imaging.
Originaltitel: Thermal detection of single photons using Dirac fermions
Abstract Detecting single photons is a crucial process in quantum science, quantum networking, biology, and advanced imaging. To detect the small quantum of energy carried in a photon, conventional mechanisms rely on energy excitation across either a semiconductor bandgap or superconducting gap that hinders their applications to low-energy photons. Here, we detect single near-infrared photons using the thermal properties of Dirac fermions in graphene. By exploiting the extremely low heat capacity of Dirac electrons near its charge neutrality point, we observe a temperature rise up to ~ 2 K using a hybrid Josephson junction. In this proof-of-principle experiment, we achieve an intrinsic quantum efficiency of 87% (75%) with dark count < 1 per second (per week), reaching an effective noise equivalent power of 2 × 10 −22 W/ $$\sqrt{{{{\rm{Hz}}}}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mrow> <mml:mi>Hz</mml:mi> </mml:mrow> </mml:msqrt> </mml:math> . The highest operation temperature is 1.2 K. Our results highlight the potential of graphene bolometers for detecting lower-energy photons from the mid-IR to microwave regimes, opening pathways to study space science in far-infrared regime, to potential applications in dark matter searches, and to advance quantum technologies across a broader electromagnetic spectrum.