Quantum State Measurement Using Coherent Transients

We present the principle and experimental demonstration of time resolved quantum state holography. The quantum state of an excited state interacting with an ultrashort chirped laser pulse is measured during this interaction. This has been obtained by manipulating coherent transients created by the interaction of femtosecond shaped pulses and rubidium atoms.

Figure 1

Simulation of CTs resulting from the excitation of the atom by a FT limited pulse (at time $t=0$) followed by a chirped pulse (centered at $t=10\mathrm{ps}$) for $\theta =0$ (black line) and $\theta =\pi /2$ (gray line). Dotted line: “Simple” CTs obtained for a single pulse at $t=10\mathrm{ps}$.

Figure 2

Experimental setup. NOPA, noncollinear optical parametric amplifier; CPA, chirped pulse amplifier.

Figure 3

Coherent transients resulting from the excitation of the atom by a FT limited pulse (at time $t=0$) followed by a chirped pulse (centered at $t=6\mathrm{ps}$). Relative phase between pulses is $\theta ={\theta }_0\simeq -0.7\mathrm{rad}$ for the lower panel and $\theta ={\theta }_0+\pi /2$ for the upper panel. Gray line, theory; black line, experiment.

Figure 4

Experimental probability amplitude reconstructed from the CTs of Fig. 3. Real part and imaginary part are shown as a function of time.

Figure 5

Reconstructed experimental probability amplitude obtained for different values of the relative phase: ${\theta }_0=3.3\mathrm{rad}$ and ${\theta }_0+2\pi /3$.