Two-photon excitation in atoms and molecules

Jing Su, Shaohao Chen, Agnieszka Jaroń-Becker +1 more

M. P. McCann, C. H. Chen, Marvin G. Payne

Yao Zhou, Zihao Chen, Jung‐Tsung Shen

Photonic Molecule, also called Photonic Dimer, is a quantum bound state of two photons. A photonic bound state has a specific entanglement of a Lorentzian anti-correlation in frequency space and two photons are in proximity due to its binding nature.Such signatures of a photonic molecule illuminates a potential tool that increases the two-photon microscopy efficiency to orders of magnitude higher. Here we numerically and analytically demonstrate the two-photon excitation efficiency between photonic molecules, long uncorrelated light pulses and ultrashort light pulses. The high excitation efficiency of a photonic molecule enables a saturation of fluorophores, such that the linear dependence of two-photon excitation crosssection does not necessarily hold. Also, we exhibits two possible methods to obtain the photonic molecules, as a fundamental possibility for a continuous photonic molecule source.

William J. Meath, B. N. Jagatap, A. E. Kondo

The dynamics and the cross sections associated with the excitation of a ground-state dipolar molecule to an excited state, by the simultaneous absorption of two photons, are discussed using the rotating wave approximation and time-dependent perturbation theory. The excitations of ten- and two-energy level representations of model dipolar molecules are used for illustrative purposes. The temporal development of the final state of the excitation process and the two-photon excitation cross sections are discussed as functions of laser intensity, laser–molecule interaction time and the two types of excitation mechanism (which are available for dipolar molecules, relative to the one mechanism for a non-polar molecule). The results are used to discuss the validity of perturbation theory treatments of the problem and various strategies for the enhancement of the intrinsically weak two-photon excitation process.

Marvin H. Mittleman

Riccardo Bruzzese, Antonio Sasso, S. Solimeno