Delay-line-based single-photon detector array for on-chip quantum simulation

Giacomo Prando

M. Hofherr, Matthias Arndt, K. Ilin +5 more

We present a concept for a time-tagged multiplexed readout of several superconducting nanowire single-photon detector elements for small arrays in ultra-short pulsed laser applications. The detector elements were coupled in an array by a superconducting delay line giving each detector element a temporal signature. The complete detector chain is biased by one bias supply. The patterning concept and the first experimental proof of principle are demonstrated on two-detector element arrays with delay times of 86 and 156 ps each made from a 5-nm NbN film on sapphire. We discuss the propagation delay of a delay line taking the geometric and kinetic inductance into account. We show that mainly the normal conducting propagation velocity defines the characteristic time of the delay line and that the inductance dependent response pulse width currently limits the maximum number of detector elements.

Alberto Politi

João Barbosa, Jack C. Brennan, A. Casaburi +4 more

One of the most important and topical challenges of quantum circuits is their scalability. Rapid single flux quantum (RSFQ) technology is at the forefront of replacing current standard CMOS-based control architectures for a number of applications, including quantum computing and quantum sensor arrays. By condensing the control and readout to single-flux-quantum-based on-chip devices that are directly connected to the quantum systems, it is possible to minimize the total system overhead, improving scalability and integration. In this article, we present a novel RSFQ device that generates multitone digital signals, based on complex pulse train sequences using a circular shift register (CSR) and a comb filter stage. We show that the frequency spectrum of the pulse trains is dependent on a preloaded pattern on the CSR, as well as on the delay line of the comb filter stage. By carefully selecting both the pattern and delay, the desired tones can be isolated and amplified as required. Finally, we propose architectures where this device can be implemented to control and read out arrays of quantum devices, such as qubits and single-photon detectors.

Ozora Iso, Kensuke Miyajima, Ryōsuke Shimizu

Distinguishing photon arrival time and position is crucial for advancing quantum technology. However, capturing spatial and temporal information efficiently remains challenging. Here, we present a novel photon detection technique to achieve a significantly more efficient measurement of frequency-entangled biphoton than conventional photon detectors. We utilize a delay-line-anode single-photon detector (DLD), which consists of a position-sensitive delay-line anode sensor behind a microchannel plate. Biphotons are obtained from the decay of biexcitons in the copper chloride semiconductor crystal. Two DLDs are coupled with a grating spectrometer exit to measure the joint spectral distributions of the biphoton. The resulting non-scanning process requires only a few minutes to obtain a temporally and spectrally resolved image, much quicker than the scanning biphoton frequency measurements such as monochromator or Fourier spectroscopy. Our technique paves the way for all experiments in multi-mode quantum science requiring coincidence measurement.

Fiore, Gaggero, Sprengers +8 more