Single-photon sources are important for integrated photonics and quantum technologies, and can be used in quantum key distribution, quantum computing, and sensing. Color centers in the solid state are a promising candidate for the development of the next generation of single-photon sources integrated in quantum photonics devices. They are point defects in a crystal lattice that absorb and emit light at given wavelengths and can emit single photons with high efficiency. The landscape of color centers has changed abruptly in recent years, with the identification of a wider set of color centers and the emergence of new solid-state platforms for room-temperature single-photon generation. This review discusses the emerging material platforms hosting single-photon-emitting color centers, with an emphasis on their potential for the development of integrated optical circuits for quantum photonics.

As the LHC luminosity is ramped up to 3 × 10 ³⁴ cm ² s ¹ and beyond, the high rates, multiplicities, and energies of particles seen by the detectors will pose a unique challenge. Only a tiny fraction of the produced collisions can be stored offline and immense real-time data reduction is needed. An effective trigger system must maintain high trigger efficiencies for the physics we are most interested in while suppressing the enormous QCD backgrounds. This requires massive computing power to minimize the online execution time of complex algorithms. A multi-level trigger is an effective solution to meet this challenge. The Fast Tracker (FTK) is an upgrade to the current ATLAS trigger system that will operate at full Level-1 output rates and provide high-quality tracks reconstructed over the entire inner detector by the start of processing in the Level-2 Trigger. FTK solves the combinatorial challenge inherent to tracking by exploiting the massive parallelism of associative memories that can compare inner detector hits to millions of pre-calculated patterns simultaneously. The tracking problem within matched patterns is further simplified by using pre-computed linearized fitting constants and relying on fast DSPs in modern commercial FPGAs. Overall, FTK is able to compute the helix parameters for all tracks in an event and apply quality cuts in less than 100 μs. The system design is defined and the performance presented with respect to high transverse momentum (high-p _T ) Level-2 objects: b jets, tau jets, and isolated leptons. We test FTK algorithms using the full ATLAS simulation with WH events up to 3 × 10 ³⁴ cm ² s ¹ luminosity and compare the FTK results with the offline tracking capability. We present the architecture and the reconstruction performance for the mentioned high-p _T Level-2 objects.

This paper proposes a design methodology for a digital library of cells resistant to cosmic radiation. Most important effects due to radiation are avoided or mitigated using ad hoc design techniques. Fault injection techniques are used to validate the design. Simulations results demonstrate that the cells designed in a 180 nm CMOS technology are tolerant to 1.5 mA current peak due to interaction with a single high-energy particle.

This paper describes the AM06 chip, which is a highly parallel processor for pattern recognition in the ATLAS high energy physics experiment. The AM06 contains memory banks that store data organized in 18 bit words; a group of 8 words is called "pattern". Each AM06 chip can store up to 131 072 patterns. The AM06 is a large chip, designed in 65 nm CMOS, and it combines full-custom memory arrays, standard logic cells and serializer/deserializer IP blocks at 2 Gbit/s for input/output communication. The overall silicon area is 168 mm² and the chip contains about 421 million transistors. The AM06 receives the detector data for each event accepted by Level-1 trigger, up to 100 kHz, and it performs a track reconstruction based on hit information from channels of the ATLAS silicon detectors. Thanks to the design of a new associative memory cell and to the layout optimization, the AM06 consumption is only about 1 fJ/bit per comparison. The AM06 has been fabricated and successfully tested with a dedicated test system.