Interferometry Ramsey

One of the most important yet simple ideas that ignited excitement about fem-tochemistry is wavepacket interferometry (Salour and Cohen-Tannoudji, 1977 Scherer, et al., 1990, 1991, 1992 Jonas and Fleming, 1995 Weinacht, et al., 1999), an optical form of Ramsey-fringe spectroscopy (Ramsey, 1990). A molecular system is subjected to two identical optical pulses created by splitting one pulse at a beam splitter. The two pulses are called the pump and the probe . The time delay between pump and probe pulses is scanned systematically using an optical delay line. The optical arrangement is very similar to that of a Fourier Transform Spectrometer (Heller, 1990). The difference in the paths traveled by the pump and probe pulses, Ad, before the two pulses are recombined at a second beam splitter corresponds to a time delay, At = Ad/c, where c is the speed of light. 

Interferometry is a long established and widely recognized optical detection technique. Its various configurations (Fizeau, Michelson, Fabry-Perot, Ramsey-Borde, Mach-Zehnder and back-scattering interferometry) have been adapted to perform optical detection on Bio-CD platforms [8] (Fig. 4). 

F. L Kien, G. Rempe, W. P. Schleich, and M. S. Zubairy. Atom localization via Ramsey interferometry A coherent cavity field provides a better resolution. Physical Revew A 1997 Oct ... 

An experimental approach to realize quantum logic gates based atomic Ramsey interferometry is presented in Sect. 6.5. The quantum bits are represented by atoms. A beam of atoms is sent through a microwave resonator. The resonator provides the necessary interaction between the atoms to perform quantum logic gates. This is an example for the concept of flying qubits. Experiments along these lines are carried out at the Ecole Normale Superiore in Paris. 

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