Superconducting nanowire single-photon detectors with non-periodic dielectric multilayers

Taro Yamashita,Kentaro Waki,Hirotaka Terai,Robert H Hadfield,Robert A Kirkwood,Shigehito Miki

doi:10.1038/srep35240

Abstract

We present superconducting nanowire single-photon detectors (SSPDs) on non-periodic dielectric multilayers, which enable us to design a variety of wavelength dependences of optical absorptance by optimizing the dielectric multilayer. By adopting a robust simulation to optimize the dielectric multilayer, we designed three types of SSPDs with target wavelengths of 500 nm, 800 nm, and telecom range respectively. We fabricated SSPDs based on the optimized designs for 500 and 800 nm, and evaluated the system detection efficiency at various wavelengths. The results obtained confirm that the designed SSPDs with non-periodic dielectric multilayers worked well. This versatile device structure can be effective for multidisciplinary applications in fields such as the life sciences and remote sensing that require high efficiency over a precise spectral range and strong signal rejection at other wavelengths.

Highlights

Used for SSPDs as a mirror for shorter wavelengths to enhance the optical absorptance so far[10,11], the non-periodic DML structures shown in the present paper could provide new functionalities to the wavelength dependence of the optical absorptance of SSPDs
A straightforward way to optimize the DML design in SSPD is to perform a numerical simulation of the optical absorptance in the nanowire with changing thicknesses of each layer in the DML using finite element analysis (FEA) and so on[19,20,21]
We assumed a twodimensional stack structure with the grid NbN layer, as shown in Fig. 1, and calculated the wavelength dependence of the optical absorptance in the NbN nanowire on the DML obtained from the previous optimization process

Summary

Results

A straightforward way to optimize the DML design in SSPD is to perform a numerical simulation of the optical absorptance in the nanowire with changing thicknesses of each layer in the DML using finite element analysis (FEA) and so on[19,20,21]. According to the optimization process described above, we designed two types of SSPDs on the non-periodic DML with a high optical absorptance range near 800 nm (Design I) and 500 nm (Design II), which are important wavelengths for applications in quantum optics[5] and life sciences[13,14], respectively For both designs, we fixed the thickness of the NbN layer to 10 nm. The GRIN lenses can focus the incident light spot to ~28 μmon the device active area Both packages enabled high efficiency optical coupling. SDE was determined by SDE =(Routput −RDCR)/Rinput, where Routput is the SSPD output pulse rate, RDCR is the dark count rate (DCR), and Rinput is the input photon rate of the cryocooler system

Experimental Results and Discussion

Author Contributions

Additional Information