Paper "Efficient Single-Photon Detection with 7.7 ps Time Resolution for Photon-Correlation Measurements" published in ACS Photonics

News - 31 July 2020 - Communication ImPhys

Iman Zadeh (1st author), Jin Chang (PhD student), Jereon Swens (bachelor student), Yuri Staaden (stagiaire) and Silvania Pereira in collaboration with KTH (Sweden), Tianjin University (China) and Single Quantum have published an article on the development and applications of very efficient single photon detectors with 7.7. ps time resolution.

In an arrangement of 4 pixels of such detectors next to each other, they succeed in performing antibunching measurements (second order quantum correlations) on a single photon emitter based on a semiconductor nanowire quantum dot. These photon correlations showed a strong antibunching (almost zero coincidences) when the correlations between the pixels were measured at zero time delay.


A broad range of scientific and industrial disciplines require precise optical measurements at very low light levels. Single-photon detectors combining high efficiency and high time resolution are pivotal in such experiments. By using relatively thick films of NbTiN (8–11 nm) and improving the pattern fidelity of the nanostructure of the superconducting nanowire single-photon detectors (SNSPD), we fabricated devices demonstrating superior performance over all previously reported detectors in the combination of efficiency and time resolution. Our findings prove that small variations in the nanowire width, in the order of a few nanometers, can lead to a significant penalty on their temporal response. Addressing these issues, we consistently achieved high time resolution (best device 7.7 ps, other devices ∼10–16 ps) simultaneously with high system detection efficiencies (80–90%) in the wavelength range of 780–1000 nm, as well as in the telecom bands (1310–1550 nm). The use of thicker films allowed us to fabricate large-area multipixel devices with homogeneous pixel performance. We first fabricated and characterized a 100 × 100 μm2 16-pixel detector and showed there was little variation among individual pixels. Additionally, to showcase the power of our platform, we fabricated and characterized 4-pixel multimode fiber-coupled detectors and carried out photon-correlation experiments on a nanowire quantum dot resulting in g2(0) values lower than 0.04. The multipixel detectors alleviate the need for beamsplitters and can be used for higher order correlations with promising prospects not only in the field of quantum optics, but also in bioimaging applications, such as fluorescence microscopy and positron emission tomography. 

Interested in reading this article? 

Efficient Single-Photon Detection with 7.7 ps Time Resolution for Photon-Correlation Measurements
Iman Esmaeil Zadeh et al., ACS Photonics 2020, 7, 1780-1787