TY - CHAP
T1 - Chirped pulse control of Raman coherence in atoms and molecules
AU - Chathanathil, Jabir
AU - Malinovskaya, Svetlana A.
N1 - Publisher Copyright:
© 2024 Elsevier Inc.
PY - 2024/1
Y1 - 2024/1
N2 - A novel chirped pulse control scheme is presented based on coherent anti-Stokes Raman spectroscopy (C-CARS) aiming at maximizing the vibrational coherence in atoms and molecules. The scheme utilizes chirping of the three incoming pulses: the pump, the Stokes, and the probe, in the four-wave mixing process of C-CARS to fulfill the adiabatic passage conditions. The derivation of the scheme is based on simplifying the four-level system into a “super-effective” two-level system via rotating wave approximation and adiabatic elimination of the excited state manifold. The robustness, spectral selectivity, and adiabatic nature of C-CARS method may prove useful for sensing, imaging, and detection. It is demonstrated that the selectivity in excitation of vibrational degrees of freedom can be controlled by carefully choosing the spectral chirp rate of the pulses. The C-CARS control scheme is applied to a surrogate methanol molecule to generate an optimal anti-Stokes signal backscattered from a cloud of molecules a kilometer away. The theory is based on the solution of the coupled Maxwell–Liouville–von Neumann equations and focuses on the quantum effects induced in the target molecules by the control pulse trains. The propagation effects of pulses through the medium are evaluated and the buildup of the molecular-specific anti-Stokes signal is demonstrated numerically. A deep learning technique, using Convolutional Neural Networks (CNNs), is implemented to characterize the control pulses and evaluate time-dependent phase characteristics from them. The effects of decoherence induced by spontaneous decay and collisional dephasing are also examined. Additionally, we present the technique of Fractional Stimulated Raman Adiabatic Passage (F-STIRAP) and demonstrate that it can be utilized for remote detection in a multilevel system by creation of a maximally coherent superposition state.
AB - A novel chirped pulse control scheme is presented based on coherent anti-Stokes Raman spectroscopy (C-CARS) aiming at maximizing the vibrational coherence in atoms and molecules. The scheme utilizes chirping of the three incoming pulses: the pump, the Stokes, and the probe, in the four-wave mixing process of C-CARS to fulfill the adiabatic passage conditions. The derivation of the scheme is based on simplifying the four-level system into a “super-effective” two-level system via rotating wave approximation and adiabatic elimination of the excited state manifold. The robustness, spectral selectivity, and adiabatic nature of C-CARS method may prove useful for sensing, imaging, and detection. It is demonstrated that the selectivity in excitation of vibrational degrees of freedom can be controlled by carefully choosing the spectral chirp rate of the pulses. The C-CARS control scheme is applied to a surrogate methanol molecule to generate an optimal anti-Stokes signal backscattered from a cloud of molecules a kilometer away. The theory is based on the solution of the coupled Maxwell–Liouville–von Neumann equations and focuses on the quantum effects induced in the target molecules by the control pulse trains. The propagation effects of pulses through the medium are evaluated and the buildup of the molecular-specific anti-Stokes signal is demonstrated numerically. A deep learning technique, using Convolutional Neural Networks (CNNs), is implemented to characterize the control pulses and evaluate time-dependent phase characteristics from them. The effects of decoherence induced by spontaneous decay and collisional dephasing are also examined. Additionally, we present the technique of Fractional Stimulated Raman Adiabatic Passage (F-STIRAP) and demonstrate that it can be utilized for remote detection in a multilevel system by creation of a maximally coherent superposition state.
KW - Adiabatic passage
KW - Coherent anti-Stokes Raman spectroscopy
KW - Convolutional neural networks
KW - Dressed state analysis
KW - Quantum control
KW - Remote detection
KW - Ultrafast Chirped pulse
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U2 - 10.1016/bs.aiq.2023.07.002
DO - 10.1016/bs.aiq.2023.07.002
M3 - Chapter
AN - SCOPUS:85174707699
T3 - Advances in Quantum Chemistry
SP - 225
EP - 289
BT - Advances in Quantum Chemistry
ER -