arXiv subjects

B. S. Karasik

Publications and source records attributed to B. S. Karasik.

2 recordsLinked to original sources

arXiv2010

Energy resolution of terahertz single-photon-sensitive bolometric detectors

We report measurements of the energy resolution of ultra-sensitive superconducting bolometric detectors. The device is a superconducting titanium nanobridge with niobium contacts. A fast microwave pulse is used to simulate a single higher-frequency photon, where the absorbed energy of the pulse is equal to the photon energy. This technique allows precise calibration of the input coupling and avoids problems with unwanted background photons. Present devices have an intrinsic full-width at half-maximum energy resolution of approximately 23 terahertz, near the predicted value due to intrinsic thermal fluctuation noise.

cond-mat.supr-con↗

arXiv2001

Millisecond Electron-Phonon Relaxation in Ultrathin Disordered Metal Films at Millikelvin Temperatures

We have measured directly the thermal conductance between electrons and phonons in ultra-thin Hf and Ti films at millikelvin temperatures. The experimental data indicate that electron-phonon coupling in these films is significantly suppressed by disorder. The electron cooling time $τ_ε$ follows the $T^{-4}$-dependence with a record-long value $τ_ε=25ms$ at $T=0.04K$. The hot-electron detectors of far-infrared radiation, fabricated from such films, are expected to have a very high sensitivity. The noise equivalent power of a detector with the area $1\mum^2$ would be $(2-3)10^{-20}W/Hz^{1/2}$, which is two orders of magnitude smaller than that of the state-of-the-art bolometers.

cond-mat.dis-nn↗