Breaking new ground in quantum detection with SNSPDs: the search for light-mass dark matter and high-critical-temperature superconductors

Datum

30.04.2024

Zeit

09:00 - 10:00

Sprecher

Dr. Ilya Charaev

Zugehörigkeit

University of Zurich

Sprache

en

Hauptthema

Materialien

Host

Martina Javorka

Beschreibung

The detection of individual quanta of light is important for quantum computation, fluorescence life-time imaging, single-molecule detection, remote sensing, correlation spectroscopy, and more. Thanks to their broadband operation, high detection efficiency, exceptional signal-tonoise ratio, and fast recovery times, superconducting nanowire single-photon detectors (SNSPDs) have become a critical component in these applications. Initially developed for deep-space communication and quantum information science, SNSPDs possess specific characteristics that make them particularly suited for detecting light dark matter(DM). A detector's ability to have minimal intrinsic false counts (on the order of 1 or fewer counts per day), and sensitivity to low-photon-energy (infrared) ranges are all critical factors. SNSPDs are the most advanced detectors in all three metrics, with ample room for improvement. Although these detectors have already shown promising results, they require further development before being used in the final designs for a DM experiment. In first part of my talk, I will discuss the remaining technological challenges, design, and characterization of the devices. The operation of SNSPDs based on conventional superconductors, which have a low critical temperature (TC), requires costly and bulky cryocoolers. This motivated exploration of other superconducting materials with higher TC that would enable single-photon detection at elevated temperatures, yet this task has proven exceedingly difficult. Here I show that with proper processing, high-TC superconductors can meet this challenge. We fabricated superconducting nano- and microwires out of thin flakes of Bi2Sr2CaCu2O8+δ, thin MgB2 films and La1.55Sr0.45CuO4/La2CuO4 (LSCO-LCO) bilayer films and demonstrated their singlephoton response up to 25, 20 and 8 K, respectively. The single-photon operation is revealed through the linear scaling of the photon count rate (PCR) on the radiation power. High-TC based SNSPDs exhibited single-photon sensitivity at the technologically important 1.55 Mikrometer telecommunications wavelength. This demonstration expands the family of superconducting materials for SNSPD technique, opens the prospects of raising the temperature ceiling, and raises important questions about the underlying mechanisms of single-photon detection by unconventional superconductors.

Links

• Seminars at the IFW

Letztmalig verändert: 30.04.2024, 07:39:52