Fig. 1. Illustration of (a) detector flood illumination, (b) a fiber-coupled detector, and (c) schematic of the efficiency measurement setup.

Fig. 2. Internal efficiency measurements of SNSPDs fabricated from (a) 9.5 nm and (b) 7.5 nm thick NbTiN films.

Fig. 3. (a) Photon counting rate (PCR) curves at 2700 nm of 60-120-r4 detectors from 7.5 nm (green) and 9.5 nm (blue) films, (b) PCR curves at 3001 nm of a 60-120-r4 detector/purple and a 1.1 μm×9  μm detector/red from 7.5 nm films, (c) PCR curves at 4013 nm of a 40-120-r5 detector from 6.5 nm film, and (d) yield statistics of devices made from films with different thicknesses.

Fig. 4. Fiber-coupled SNSPDs measurements of (a) SDE of detector #1 at 1310, 1625, 1550, and 2000 nm, (b) timing jitter of detector #1, (c) SDE of detector #2 at 2001 nm, and (d) DCRs of detector #2 under different conditions: no fiber (green), low-pass coated fiber (turquoise), UHNA fiber (red), and mid-IR fiber (purple) plugged in.

Table 1. Comparison of Different Mid-Infrared SNSPD Works

Table 2. Flood Illumination Measurement Results of 9.5 and 7.5 nm NbTiN-Based SNSPDs