High-efficiency superconducting nanowire single-photon detectors fabricated from MoSi thin-films

Abstract

We report on MoSi SNSPDs which achieved high system detection efficiency (87.1 ± 0.5% at 1542 nm) at 0.7 K and we demonstrate that these detectors can also be operated with saturated internal efficiency at a temperature of 2.3 K in a Gifford-McMahon cryocooler. We measured a minimum system jitter of 76 ps, maximum count rate approaching 10 MHz, and polarization dependence as low as 3.3 ± 0.1%. The performance of MoSi SNSPDs at 2.3 K is similar to the performance of WSi SNSPDs at < 1 K. The higher operating temperature of MoSi SNSPDs makes these devices promising for widespread use due to the simpler and less expensive cryogenics required for their operation. Sobolewski, "Response time characterization of NbN superconducting single-photon detectors," IEEE Trans. Appl. Supercond. 13(2), 180-183 (2003). 11. H. Takesue, S. W. Nam, Q. Zhang, R. H. Hadfield, T. Honjo, K. Tamaki, and Y. Yamamoto, "Quantum key distribution over a 40-dB channel loss using superconducting single-photon detectors," Nat. Photonics 1(6), 343-348 (2007

Characteristics of superconducting tungsten silicide WxSi1−x for single photon detection

“…Similar results can be achieved with devices from TaN which have intermediate T c values from 6 to 10 K and, consequently, the advantage of still being able to operate efficiently between 2 and 4 K [13][14][15][16]. Recent results obtained with detectors from amorphous superconducting films MoGe [17], WSi [18][19][20][21], and MoSi [22], which all have T c in the range from 5 to 7.5 K, retain the promise of significant improvement in both detection efficiency and spectral range, extending the sensitivity further into the infrared. So far, the highest detection efficiency (DE) reported for SNSPD of the order of 93% has been achieved with WSi [20].…”

Optically probing the detection mechanism in a molybdenum silicide superconducting nanowire single-photon detector

“…6 Notably, SNSPDs can be integrated into photonic circuits, 7,8 and their applications extend beyond quantum optics, including light detection and ranging, 9 integrated circuit testing, 10 and fiber optic sensing. 11 One recent important advance in the SNSPD field has been the introduction of amorphous superconductors such as tungsten silicide (WSi), 12 molybdenum silicide (MoSi) 13,14 and molybdenum germanium (MoGe). 15 SNSPDs based on these materials currently have the highest reported detection efficiencies (93% for WSi 12 ), as well as a higher fabrication yield 16 than devices made of polycrystalline materials such as niobium nitride (NbN), 1 niobium titanium nitride (NbTiN) 17 and tantalum nitride (TaN).…”

On-chip generation of photon-triplet states

“…Finally, higher repetition rates of the pump laser, e. g. by temporal multiplexing [34] will lead to increasing numbers of detectable photon triplets and indicate the scalability of our integrated device. Note that state-of-the-art detector recovery times of around 75 ns for highly efficient MoSi-based SNSPDs [35], in conjunction with detection efficiencies of η det ∼ 87%, are still the limiting factor to date rather than available repetition rates for the pump laser. By contrast, increasing the pump pulse energy will not improve the output of photon triplets at high CAR-values, because of the growing impact of higher-order photon contributions.…”