The detuning controlled maximum coherence via C-CARS

Maximizing vibrational coherence in Coherent Anti-Stokes Raman Spectroscopy (CARS) to enhance the signal response from molecules has been studied recently with various applications including remote detection. A chirp control scheme C-CARS for the creation of maximum coherence [1], determined from the conditions of adiabatic passage, is used to analyze the effects of resonance and two-photon detuning on the response from the system. Using the C-CARS, the maximum coherence is achievable for a broad range of Rabi frequency and chirp parameters in the scenario of a large one-photon detuning and the two-photon resonance. It is also found that for positive values of the chirp parameter, a non-zero two-photon detuning gives high coherence for a wide range of the Rabi frequency in the one-photon resonance. We also demonstrate the application of the C-CARS to remote detection of molecules in a framework of a semiclassical model [2].