The ability to detect single photons is crucial for quantum optics as well as for a wide number of applications. Several technologies have been developed for efficient single photon detection in the visible and near infrared. The invention of the superconducting nanowire single photon detector in 2001 enabled the development of a new class of detectors that can operate close to physical limits. Different aspects will be discussed including wavelength detection range, time resolution, dark counts, saturation rates and photon number resolution along with various applications such as Lidar, quantum communication, deep space communication, microscopy and bio-medical measurements.

Multipixel single photon detectors based on superconducting nanowires will also be discussed, including a quantum spectrometer that is based on an array of high-performance single photon By time stamping single photon detection events at the output of a spectrometer we generate data that can yield spectra as well as photon correlations such as g(2), g(3) to g (n) as well as cross correlations among different spectral lines, under pulsed excitation, transition lifetimes can also be extracted. This instrument therefore replaces a spectrometer, a streak camera, a Hanbury-Brown Twiss interferometer and operates with far higher signal to noise ratio than is possible with existing detectors that are commonly used in the infrared.

Quantum technology is our quest to harness the subtle but powerful effects of quantum mechanics for technology, particularly in computing, sensing, and communication. Since the advent of quantum mechanics 100 years ago, quantum technology has taken transformative steps from thought experiments to proof-of-concept laboratory experiments to application-ready technology products, especially in the last two decades. However, the realization of robust, scalable quantum technology hardware still faces the key challenge of making quantum systems with multi-qubit quantum states immune to environment-induced decoherence while at the same time being fully controllable in every detail.

Synchrotron and free-electron laser facilities, with their high-precision analytical capabilities, are poised to address this paradoxical (quantum) materials challenge. These most powerful x-ray photon sources offer a unique variety of methods to characterize the properties and functions of materials, interfaces, and devices on atomic length and time scales with high precision and sensitivity. This talk will provide an overview of how x-ray nano- and femtoanalytics, in particular based on most advanced diffraction-limited storage rings and high-repetition free-electron lasers, can drive materials innovation for quantum technologies.