Coherent control of matter in photonic crystal fibers

An exciting field known as “Coherent Control of Quantum Systems” emerged from previously unsuccessful attempts to employ lasers to steer chemical reactions. One of the main ideas is to use the phase coherences within a spectrally broad bandwidth laser pulse to drive quantum systems to a desired target state. In other words, we specify the initial and the final state of a quantum system and design the coherences within a laser pulse such that this goal is achieved with a maximum efficiency. Progress in this field is tightly linked to technological advances in pulse shaping, i.e. in tailoring the lasers’ spectral components, and has led to numerous achievements in communications, physics, chemistry, and life sciences. Especially, state-selective photochemistry has always been a driving force in this field, but recently many other fields have seen great impact of coherent or optimal control. In cases where the quantum system is too complicated and no predictions on the ideal laser waveform are available, self-learning algorithms are employed to circumvent this problem. The efficiency of the final quantum state population is monitored, and the algorithm optimizes the efficiency by adjusting the spectral coherences within the laser waveform. Often it is possible to extract useful information from the optimized waveform, therefore, gaining new and sometimes unexpected information on the underlying fundamental processes.