Presentation Information
[EDP1-09]Modelling of Multi-Photon Events of a Superconducting Single-Photon Nanostripe Detector for Photon Number Resolution Experiments
*Quang Nguyen1,2, Ivan Komissarov1, Roman Sobolewski1,2 (1. Department of Electrical and Computer Engineering, University of Rochester (United States of America), 2. Laboratory for Laser Energetics, University of Rochester, Rochester (United States of America))
Keywords:
Superconducting Nanostripe Single Photon Detector,Photon Number Resolution,Flux Quantum digital circuitry,Optical-to-Electronic Transducer
Purpose
This work proposes a novel photon number resolution (PNR) scheme for a single superconducting nanostripe single-photon detector (SNSPD) using superconductor single-flux-quantum (SFQ) readout electronics.
Method
We modified a known SNSPD dynamic model in the LTSpice environment to simulate multi-photon absorption events. The number of absorbed photons (1 to 5) was represented by an equivalent number of series-connected resistors, each modeling a single, photon-induced hot spot. Next, we designed a dedicated readout circuit using SFQ based circuitry to achieve PNR from a single SNSPD photoresponse output.
Results
Simulations show the rise time of a SNSPD photoresponse pulse decreases as the number of absorbed photons increases. In particular, the rise time was found to be inversely proportional to the square root of the photon number and directly proportional to the square root of the detector’s kinetic inductance. The latter indicates large meander SNSPDs with high kinetic inductance are preferable for PNR requiring applications. Furthermore, using the DC-to-SFQ converter model, we designed an SFQ circuitry, where differences in the SNSPD photoresponse rise times due to a different number of input photons were converted into SFQ pulses and demonstrated that time differences between SFQ pulses triggered by different photon-number events were significant and easily resolvable.
Consideration
The results confirm a trade-off that higher kinetic inductance improves timing resolution for PNR but inherently limits the detector's maximum counting rate. Successful integration with SFQ logic confirms the scheme's practicality.
Conclusion
Our simulations validate the proposed SFQ-based readout scheme for PNR. The deterministic relationship between SNSPD photoresponse pulse rise time and the corresponding photon number provides a viable mechanism for PNR of a single SNSPD. The coupled low-power, superconductor SFQ electronics enables to resolve the actual number of photons incident on the detector.
This work proposes a novel photon number resolution (PNR) scheme for a single superconducting nanostripe single-photon detector (SNSPD) using superconductor single-flux-quantum (SFQ) readout electronics.
Method
We modified a known SNSPD dynamic model in the LTSpice environment to simulate multi-photon absorption events. The number of absorbed photons (1 to 5) was represented by an equivalent number of series-connected resistors, each modeling a single, photon-induced hot spot. Next, we designed a dedicated readout circuit using SFQ based circuitry to achieve PNR from a single SNSPD photoresponse output.
Results
Simulations show the rise time of a SNSPD photoresponse pulse decreases as the number of absorbed photons increases. In particular, the rise time was found to be inversely proportional to the square root of the photon number and directly proportional to the square root of the detector’s kinetic inductance. The latter indicates large meander SNSPDs with high kinetic inductance are preferable for PNR requiring applications. Furthermore, using the DC-to-SFQ converter model, we designed an SFQ circuitry, where differences in the SNSPD photoresponse rise times due to a different number of input photons were converted into SFQ pulses and demonstrated that time differences between SFQ pulses triggered by different photon-number events were significant and easily resolvable.
Consideration
The results confirm a trade-off that higher kinetic inductance improves timing resolution for PNR but inherently limits the detector's maximum counting rate. Successful integration with SFQ logic confirms the scheme's practicality.
Conclusion
Our simulations validate the proposed SFQ-based readout scheme for PNR. The deterministic relationship between SNSPD photoresponse pulse rise time and the corresponding photon number provides a viable mechanism for PNR of a single SNSPD. The coupled low-power, superconductor SFQ electronics enables to resolve the actual number of photons incident on the detector.