NIST develops SNSPD detector array for mid-IR

Image Sensors World        Go to the original article... covered a recently published paper titled "A 64-pixel mid-infrared single-photon imager based on superconducting nanowire detectors" by a team from NIST in the journal Applied Physics Letters. 


A large-format mid-infrared single-photon imager with very low dark count rates would enable a broad range of applications in fields like astronomy and chemistry. Superconducting nanowire single-photon detectors (SNSPDs) are a mature photon-counting technology as demonstrated by their figures of merit such as high detection efficiencies and very low dark count rates. However, scaling SNSPDs to large array sizes for mid-infrared applications requires sophisticated readout architectures in addition to superconducting materials development. In this work, an SNSPD array design that combines a thermally coupled row-column multiplexing architecture with a thermally coupled time-of-flight transmission line was developed for mid-infrared applications. The design requires only six cables and can be scaled to larger array sizes. The demonstration of a 64-pixel array shows promising results for wavelengths between 3.4 μm and 10 μm, which will enable the use of this single-photon detector technology for a broad range of new applications.


NIST researchers have unveiled a new kind of single-photon detector array that can identify individual particles of light (photons). It's useful for spectroscopy, where scientists observe how molecules absorb different colors (or wavelengths) of light. Each molecule has its own color fingerprint on the light spectrum.

This particular detector can catch single photons in the mid-infrared. Here's how the array works: Multiple super-cold detectors are connected to one another (shown above) in a grid of sorts with an electrical current flowing through. When a photon strikes one of the detectors, it creates a hot spot and acts as a dam to block the current for a short amount of time.

The researchers developed a new technique to determine where, along the columns and rows, the hot spot is. From there, they can create single-photon pictures.

The whole setup is challenging because mid-infrared waves are longer and have less energy to cause the hot spots, compared to visible light, for example. But the scientists have a few tricks up their sleeve and used them to make it work.

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