Photon correlation effects in second harmonic generation

G. S. Holliday

The study investigates antibunching, sub-Poissonian statistics, and photon correlation functions in the pump and harmonic modes of the seventh harmonic generation process.We investigated various approaches to photon antibunching by solving the generalised interaction Hamiltonian in the Heisenberg picture using short-time approximation.It is inferred that the number of pump photons, coupling of the field strength, and interaction times significantly influence photon antibunching.It is observed that third-order antibunching in the pump mode has greater nonclassicality than second-and first-order antibunching.In the harmonic mode, the nonclassical effect is found to be less pronounced and becomes more evident as the interaction time decreases.The first-order Hamiltonian interaction induces a stronger nonclassical effect than the second-order interaction.The interaction of a coherent pump field with a nonzero harmonic field leads to photon clustering and bunching effects.Finally, photon antibunching appears most pronounced, indicating nonclassicality, as the second-order correlation function decreases.This confirms that antibunching is a fundamental quantum property of light.

Rupesh Singh, Dilip Kumar Giri

We studied photon antibunching in the pump and the harmonic modes of the sixth harmonic generation process. The generalized interaction Hamiltonian is solved for several particular cases in the Heisenberg picture, and the possibility of observing photon antibunching is investigated using the short-time approximation technique. It is shown that the photon antibunching in the pump field depends on the number of pump photons, the interaction time, and the coupling of the field between the modes. With the same amount of pump photons, we deduced that third-order photon antibunching is more nonclassical than second- and first-order photon antibunching. In this process, the effect of photon antibunching is not seen in the harmonic mode over pump mode. It is shown that photon antibunching is more noticeable with shorter interaction times as the depth of nonclassicality increases and the second-order correlation function decreases. The first-order Hamiltonian interaction, which stimulates both pump and harmonic fields, is demonstrated to be more nonclassical than the second-order Hamiltonian interaction. It is clear that the coherent state, or vacuum state, of a pump field with a nonzero harmonic field creates photon clusters because the pump field causes interaction, which leads to bunching effects. It is interpreted that the degree of photon antibunching is maximum in the regions where the second correlation function is minimum. Photon antibunching has been shown to be one of the quantum properties of light.

Yujiang Qu

Robert Prevedel, K. M. Schreiter, Jonathan Lavoie +1 more

Energy-time entangled photon pairs remain tightly correlated in time when the photons are passed through equal magnitude, but opposite in sign, dispersion. A recent experimental demonstration has observed this effect on ultrafast time scales using second-harmonic generation of the photon pairs. However, the experimental signature of this effect does not require energy-time entanglement. Here, we demonstrate a direct analogue to this effect in narrow-band second-harmonic generation of a pair of classical laser pulses under similar conditions. Perfect cancellation is observed for fs pulses with dispersion as large as 850 fs${}^{2}$, comparable to the quantum result, but with an ${10}^{13}$-fold improvement in signal brightness.

Daniel F. Walls, C. T. Tindle