Physics Letters A 319 (2003) 448–460 www.elsevier.com/locate/pla Single photon fluorescence under non-Poissonian excitation D. Felinto a , A.Z. Khoury b , S.S. Vianna a,∗ a Departamento de Física, Universidade Federal de Pernambuco, Cidade Universitária, 50670-901, Recife, PE, Brazil b Instituto de Física, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza S/N, 24210-340, Niterói, RJ, Brazil Received 12 April 2003; received in revised form 15 October 2003; accepted 22 October 2003 Communicated by R. Wu Abstract We investigate the problem of a two-level atom excited by a single photon source with variable statistics. Analytical expressions are obtained and compared to Monte Carlo simulations considering the correlation between absorption and stimulated emissions. Photon number fluctuations and time correlations are calculated showing the influence of the excitation statistics.  2003 Elsevier B.V. All rights reserved. PACS: 42.50.Dv; 42.50.Lc; 42.55.-f Keywords: Single photon fluorescence; Non-Poissonian excitation; Monte Carlo simulation 1. Introduction One of the seminal works in quantum optics by Kimble et al. [1] studied the antibunched photoelectric counts observed in resonance fluorescence of sodium atoms continuously excited by a dye laser. This anti- bunching is one of the statistical properties of light that cannot be explained in the framework of a classical electromagnetic field theory. Later, it was also shown that the photon number statistics in resonance fluo- rescence was sub-Poissonian [2]. However, measure- ments of the sub-Poissonian character are usually dif- ficult due to the isotropic nature of spontaneous emis- sion which severely limits the photon collection effi- * Corresponding author. E-mail address: vianna@ufpe.br (S.S. Vianna). ciency thus providing an almost Poissonian statistics. The best results were obtained in ion traps [3] (mainly due to improvements in collection efficiency) and in measurements of atomic beam deflection [4,5]. In the last years we have witnessed an incredi- ble development of a new kind of light source based on single photon emissions [6–11]. This development is motivated mainly by the potential applications of such sources to quantum computation and quantum communication protocols relying on the controlled ex- change of individual quantum bits (q-bits) [12]. Single photon sources have been produced with quantum dots in semiconductor structures [6–9], individual mole- cules embedded in polymer thin films [11], and color centers in diamonds [13]. The single photon emission is triggered by a pulsed laser excitation, and confine- ment into a microcavity may provide directional spon- taneous emission. 0375-9601/$ – see front matter  2003 Elsevier B.V. All rights reserved. doi:10.1016/j.physleta.2003.10.055