SC516

The course covers single-photon, entanglement and some other non-classical light sources, single-photon detectors and their applications.  

The single-photon technology is truly interdisciplinary and covers multiple fields, including optics, electronics and fundamental physics. Because faint light occurs in diverse practical settings, from fundamental physics to remote sensing and biology, new measurement methods for these light-emitting systems can be developed based on light characterization, and often by merely counting emitted photons. In addition, we will discuss the use of single-photons and entangled states for quantum networks. 

We will talk about different methods to generate single photon light and other nonclassical states, including entangled states. Deterministic sources are based on single quantum emitters such as a single atom, a single molecule or a quantum dot. Probabilistic sources use optical nonlinearities and rely on parametric down-conversion and four-wave mixing. Yet, quantum memory-based sources may combine the probabilistic excitation with deterministic single photon emission. 

We will review the characteristics of the ideal single photon state and learn how to characterize the state via a measurement. Traditionally, second-order correlation functions are used for characterization. Other methods may enhance our understanding of the state. We will discuss practical examples where properties of the light field and even underlying physics of light emitters are uncovered via those measurements. 

There exists a variety of single-photon detectors, from photomultiplier tubes to avalanche photodiodes and superconducting sensors. Detectors, due to their complexity, cannot be simply described by detection efficiency. Other parameters, such as deadtime and afterpulsing, play an important role. 

Single photons are a natural choice for quantum communication. Indeed, photons do not readily interact with atoms in transparent media. We will review basic quantum communication protocols, such as quantum key distribution, entanglement swapping and quantum teleportation and their implementation in photonic networks.

This course is designed as an introduction to single-photon technology and should help participants to obtain basic working knowledge that enables their entry into the field. Specifically,  

• Learn the properties of single-photon sources and detectors. 
• Obtain basic knowledge on components of a photonic quantum network. 
• Develop a photon-counting-based application on a conceptual level.  
• Recognize the benefit of single-photon sources and detectors for their research. Find ideas to enhance their application(s). 
• Learn the proper way to understand measurement results with faint light states.  
• Learn key statistical methods relevant to faint light measurement and characterization. 
• Become knowledgeable of present and future trends in single-photon research and quantum networks and identify own strategic goals in this field. 

Graduate students, post-docs, faculty, researchers and technical personnel in academia, industry and government labs looking for an introduction in a single-photon technology and related fields.  
The only requirement to comprehend and benefit from the course is an undergraduate course in physics/ applied physics/electrical engineering covering the basics of optics. An undergraduate course on quantum mechanics would be helpful, but optional. The information presented in this Short Course should also be useful to patent attorneys and legal professionals who are active in a single photon technology area. 

Dr. Sergey V. Polyakov is the project leader in Quantum Measurement division, Physical Measurement Laboratory at NIST. His projects aim at developing quantum methods of characterization of faint light with applications ranging from classical and quantum networking to quantum-enabled biophotonics. Sergey contributed to early research efforts in quantum repeaters. He developed innovative methods of single photon source characterization that leads to in-situ, non-invasive measurement of underlying physics of single-photon emitters. Recently, he invented and developed a new class of optical receivers for classical communications that use quantum measurement. He performed one of the most accurate single photon detector characterizations. Sergey is a Fellow of The Optical Society and has served as a General Chair of the CLEO Conference (2021), and Optica Nonlinear Photonics Topical Meeting (2022).