Nanobolometer with ultralow noise equivalent power

Since the introduction of bolometers more than a century ago, they have been used in various applications ranging from chemical sensors, consumer electronics, and security to particle physics and astronomy. However, faster bolometers with lower noise are of great interest from the fundamental point of view and to find new use-cases for this versatile concept. We demonstrate a nanobolometer that exhibits roughly an order of magnitude lower noise equivalent power, $$20\,{\mathrm{zW}}/\sqrt {{\mathrm{Hz}}}$$ , than previously reported for any bolometer. Importantly, it is more than an order of magnitude faster than other low-noise bolometers, with a time constant of 30 μs at $$60\,{\mathrm{zW}}/\sqrt {{\mathrm{Hz}}}$$ . These results suggest a calorimetric energy resolution of 0.3 zJ = h × 0.4 THz with a time constant of 30 μs. Further development of this nanobolometer may render it a promising candidate for future applications requiring extremely low noise and high speed such as those in quantum technology and terahertz photon counting. Bolometers have been used for over a century for a wide range of applications with recent developments aiming at reducing noise and increasing readout speed. The authors present a nanobolometer with an order of magnitude lower noise and over an order of magnitude increased readout speed than previously shown, making this instrument a promising candidate for applications in quantum and terahertz technology.