Application Notes

An infrared streak camera

Pairing an SNSPD with a Fourier transform spectrometer

By pairing a superconducting nanowire single photon detector (SNSPD) with a Fourier transform spectrometer, a high-performance system with exceptional sensitivity and temporal resolution can be obtained.

With SNSPDs boasting >90% quantum efficiency in the near-infrared and up to 35% in the mid-infrared, this combination enables unprecedented sensitivity for time-resolved spectral measurements. Download the application note to explore how this system has been used by a research group at the University of Technology in Eindhoven, in collaboration with Nireos and PicoQuant, to study carrier dynamics in semiconductors and uncover new insights into photoluminescence spectra behavior.

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Using an SNSPD and an electro-optical modulator to sample fast RF signals

There are two types of oscilloscopes to measure radio frequency (RF) signals: Real-time and Sampling oscilloscopes. Typically, sampling oscilloscopes provide more electrical bandwidth, but they need a repetitive signal to analyze. Often sampling scopes are used to analyze optical signals.

In this application note, we showcase how a superconducting single-photon detector (SNSPD) can be used to analyze low-power optical signals together with a time tagger. In the present work, we characterize a 200 ps wide pulse from a fast pulse generator.

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Photon Number Resolving Detectors

Photon number resolving (PNR) detectors can recognize the number of arriving photons in one detection event.

Until now, single-photon detectors based on superconducting nanowires (SNSPDs) could only resolve the photon number by making a multi-pixel array of SNSPDs connected to a read-out circuit that determine how many pixels click simultaneously. However, the need for more pixels increases the cost of the system and still has the probability that multiple photons are absorbed in the same pixel, reducing the photon number information.

Single Quantum has improved the timing jitter and recovery time of SNSPDs. This allows for a less complicated solution for PNR: with only one SNSPD, the PNR can be measured through a simple jitter measurement.

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Using an Oscilloscope as a Correlator

Photon-correlation measurements are the backbone of quantum-optics experiments and are performed with dedicated hardware; a so-called “correlator”.

Under some circumstances, it would be beneficial to perform correlation measurements with an oscilloscope, because pulses and trigger levels can be visualized and the timing jitter is superior.

Typically, photon correlation experiments operate below 100 kCnts/s photons on each correlation channel. In this situation an RTO scope misses only a few percent of the incoming photons. In return a scope allows to perform the experiment in a What You See Is What You Get approach, making it easier to use than a traditional correlator.

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Imaging the deep brain with infrared light

The field of brain imaging uses various techniques to image the structure and function of the nervous system. It is an emerging discipline crossing the boundary of medicine and neuroscience that has seen tremendous advances in recent years. 

The use of SNSPDs coupled to a confocal microscope operating in the SWIR opens up the possibility of
imaging biological structures 2 to 4 times deeper than previously possible with one-photon confocal fluorescence microscopy.

In this article, we show deep brain imaging achieved with infrared light while utilizing SNSPD’s.

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