Photon antibunching

Figure C 1.5.10. Nonnalized fluorescence intensity correlation function for a single terrylene molecule in p-terjDhenyl at 2 K. The solid line is tire tlieoretical curve. Regions of deviation from tire long-time value of unity due to photon antibunching (the finite lifetime of tire excited singlet state), Rabi oscillations (absorjDtion-stimulated emission cycles driven by tire laser field) and photon bunching (dark periods caused by intersystem crossing to tire triplet state) are indicated. Reproduced witli pennission from Plakhotnik et al [66], adapted from [118].

Basche T, Moerner W E, Orrit M and Talon FI 1992 Photon antibunching in the fluorescence of a single dye molecule trapped in a solid Phys. Rev. Lett. 69 1516-19... 

R. Hanbury Brown, R., Twiss, R.Q., 1956, Correlation between photons in two coherent beams of light. Nature 177, 27 Hong, C.K., Ou, Z.Y., Mandel, L., 1987, Measurement of subpicosecond time intervals between two photons by interference, Phys. Rev. Lett. 59, 2044 Kimble, H.J., Dagenais, M., Mandel, L., 1977, Photon Antibunching in Resonance Fluorescence, Phys. Rev. Lett. 39, 691... 

Photon Antibunching Behavior of Organic Dye Nanocrystals on a Transparent Polymer Film 217... 

S. Machida, H. Kasai, H. Nakanishi, H. Oikawa, A. Itaya Photon antibunching in the emission from a single organic dye nanocrystal.Jpn.J. Appl. Phys. 2007, 46, L268-L270. Copyright the Japan Society of Applied Physics. Reproduced with permission. 

In this section, we have demonstrated that a single organic dye nanocrystal comprised of many chromophores shows photon antibunching when the size is sufficiently small. The present results indicate that molecular assemblies can also be considered as candidates for new single-photon sources. 

Photon Antibunching and Magnetic Resonance of Single Molecular Spins... 

If g(2 (r) < g (0), the probability of detecting the second photon decreases with the time delay t, indicating bunching of photons. On the other hand, if (2)(t) > g(2)(0), we have the effect of antibunching of photons. Photon antibunching is another signature of quantum character of the field. For t = 0, we have... 

In Fig. 14, we plot the correlation functions (146) and (147) computed from the equations of motion (96) for the case of degenerate transitions (A = 0) and two different values of p p = 0 corresponding to the case of perpendicular dipole moments, and p = 0.99 corresponds to almost parallel dipole moments. We have chosen p < 1 to avoid population trapping, which can appear for p = 1. The correlations show the characteristic photon antibunching effect [59] that g1-11 (x)... 

The photon antibunching according to the y th (y = I, II, III) definition occurs if the normalized intensity correlation function gf t, t + x) increases from its initial value at x 0 ... 

Figure 10. Illustration of eight different predictions of photon antibunching of quantum fields, corresponding to the cases analyzed in Table III and Fig. 9. The two-time signal-mode correlation functions Agi(t,t + x) (dashed curves), Agn(t,t + t) (dot-dashed), and Agni(M + f) (solid) are plotted in their dependence on the rescaled time separation kt for fixed values of the evolution time (case 1) Kt = 2.8, (2) kt = 2.6, (3) kt = 0.1, (4) kt = 0.1, (5) Kt = 1.0, (6) kt = 2.3, (7) Kt = 0.7, and (8) Kt — 1.8. Signal and idler modes are initially in Fock states with Na — 3 and Nt, = 1 in cases 2 and 3, or with Na —2 and Nb — 1 in all other cases.

As pointed out in many papers photon antibunching is a purely quantum phenomenon (see e.g. Refs. (2, 15). The fluorescence of a single ion displays the additional nonclassical property that the variance of the photon number is smaller than its mean value (i.e. it is sub-Poissonian). This is because the single ion can emit only a single photon and has to be re-excited before it can emit the next one which leads to photon emissions at almost equal time intervals. The sub-Poissonian statistics of the fluorescence of a single ion has been measured in a previous experiment (14) (see also Ref. (16) for comparison). 

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