Figure 1

(Color online) Cross correlation in the transmitted intensity fluctuations of Zeeman EIT vs two-photon detuning as measured (symbols) and calculated (lines). In (a) regions I–III of correlation, anticorrelation, and return to correlation described in the text are visible, while (b) shows the central region of (a) near zero two-photon detuning. The linewidth of the central peak is approximately the same for 60 and $100\mu \text{W}$ data, and broader for $153\mu \text{W}$ data, which was taken at higher magnetic gradient, showing that intrinsic decoherence determines the narrow resonance width. Only negative detuning is shown, as the experimental results are symmetric with two-photon detuning. 2 Torr Ne buffer gas and 3 mm laser beam diameter. In the calculation, an intrinsic decay rate of $\approx 2\pi \times 100\text{Hz}$ was used for all laser powers.Reuse & Permissions

Figure 2

(Color online) (a) Measured noise spectra of total transmitted power for hyperfine EIT. Two-photon detunings of (i) 1, (ii) 10, (iii) 50, and (iv) 80 kHz. (b) Dip center frequencies vs two-photon detuning (symbols); line represents dip $center=detuning$. (c) Widths of dips and EIT resonances are equal at all input laser powers. (Two-photon $\text{detuning}=50\text{kHz}$.) Laser power $\approx 170\mu \text{W}$ for plots (a) and (b). 0.85 mm beam size and 2 Torr Ne buffer gas for (a)–(c).Reuse & Permissions

Figure 3

(Color online) (a) and (b) Measured transition between resonant (i) suppression and (ii) enhancement of laser phase-noise-to-intensity-noise conversion in hyperfine EIT. (See text for experimental details.) (c) Examples of calculated noise spectra for no two-photon phase noise (dip) and extra phase noise (peak) at $\Delta =50\text{kHz}$.Reuse & Permissions