Pulsed electrically driven single-photon sources on diamond

• Applicant: Dr. Dmitry Fedyanin, Ph.D. (†)
• Subject Area: Theoretical Condensed Matter Physics ; Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2023 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 527140061

Efficient optoelectronic devices exploiting the quantum nature of light are in great demand for emerging quantum information, communication and metrology technologies. One of the essential elements of these devices is an on-demand single-photon source (SPS), which produces optical pulses containing strictly one photon at predetermined times. An on-demand SPS can be designed using a two-level-like quantum system capable of single photon emission. From a practical point of view, it is highly desirable that the quantum system is triggered by short electric pulses, since electrical pumping is the only possibility to achieve high energy efficiency, integrability, and scalability of SPSs. Color centers in diamond have recently emerged as one of the most promising quantum systems for practical SPSs. It has been shown that these emitters can be excited electrically and demonstrate high brightness at room and even higher temperatures. However, all studies of color centers in diamond dealt only with the steady-state direct-current (DC) regime when photons were emitted at random times, while most practical applications of quantum technologies require the SPS to produce single photons on demand. The aim of the present project is to theoretically investigate for the first time the possibility of on-demand generation of single-photon pulses from single NV and SiV centers in diamond under pulsed electrical excitation and show how to produce single-photon pulses at a high pulse repetition rate. Our most recent preliminary results demonstrate that due to the exceptionally low density of free electrons in diamond devices, traditional color center excitation schemes, when a color center is placed in the i-type region of the p-i-n diamond diode, fundamentally cannot be used to efficiently generate one-photon pulses at a high repetition rate despite the fact that such schemes can be used produce more than 10^6 photons/s at random times in the DC regime. We will first reveal the limits of diamond single-photon emitting diodes (SPEDs) based on traditional p-i-n structures, such as the maximum possible rate of generation of single-photon pulses and the maximum single-photon purity of these pulses. Then we will rethink the design principles previously used for the development of semiconductor-based SPEDs to increase the single-photon purity of emitted pulses at a high generation rate of optical pulses. In particular, we will focus on p-n and Schottky diamond diodes instead of the commonly used p-i-n structures. We expect to numerically demonstrate that such structures can give the possibility to achieve the single-photon purity of emitted pulses higher than 95% (i.e., the probability of producing two or more photons per pulse is less than 5%) at a single-photon pulse generation rate of 10^4-10^5 single-photon pulses per second at room temperature.

• DFG Programme: WBP Position