Near infrared ultra-bright triggered single photon source from nano-diamonds
Stefania Castelletto, Igor Aharonovich, David Simpson +2 more
Quantum communication and quantum metrology established a demand for an accessible solid state systems which can generate a stream of single photons on demand [1]. Although single photon emission has been demonstrated from quantum dots (QD)[1,2], single molecules [3] and nanowires [4], their practical operation is limited by the temperature or photostability. Diamond crystals, however, are the most promising platform for generation of robust, photo-stable, single photons at room temperature [5,6]. Nevertheless, out of more than 500 existing optical centers in diamond only three known centers demonstrated a clear single photon emission: the nitrogen-vacancy complex [6,7], the silicon-vacancy complex [8] and the nickel-nitrogen complex [9,10]. Recent progress in materials science and fabrication techniques of diamond color centers unveiled novel quantum emitters with photo-physical properties surpassing the current mainstream [11,12,13]. Consequently, the versatility of the diamond lattice to host various impurities which give luminescence signals lead to a dramatic discovery of ultra bright single photon emitters operating in the MHz regime [14]. These new centers, comparable with QD in terms of brightness [1], but have the tremendous advantage of their room temperature operation and photo-stability. Furthermore, it opened a new avenue to investigate essentially an unknown group of single photon emitters. A brief description of the fabrication methods and a detailed quantum optical characterization of this class of diamond emitters is the subject of this presentation. In particular we will present the photo-physical properties of a novel family of single photon emitters, most likely originated from Cr impurities within the chemical vapor deposition grown nano-diamond crystals. We concentrate on the typical emission lines in the range of 740 - 790 nm, which exhibit single photon emission with count rate in the range of 0.8-3.2 106 counts/s at the limit of infinite optical excitation power, and life time as short as 1 ns. Even more, some of the emitters exhibit a photon statistics without any photon bunching, indicating a two-level system with unitary quantum efficiency. We will also show preliminary results of a resonant excitation at 4 K. We will highlight future directions to optimize these sources and avenues to investigate the fundamental properties of these centers.
•Jan 1, 2009•0 citations