Observation of coherent two-photon emission from the first vibrationally excited state of hydrogen molecules

Abstract

In this paper, we describe an experiment which was conducted to explore the macro-coherent amplification mechanism using a two-photon emission process from the first vibrationally-excited state of para-hydrogen molecule. Large coherence in the initial state was prepared by the adiabatic Raman method, and the lowest Stokes sideband was used as a trigger field. We observed the coherent two-photon emission consistent with the expectation of the Maxwell-Bloch equation derived for the process, whose rate is larger by many orders of magnitude than that of the spontaneous emission.

Superradiant searches for dark photons in two stage atomic transitions

“…The use of two stage superradiant atomic transitions for the production and detection of weakly coupled particles was proposed and studied extensively by Yoshimura et al [32][33][34][35][36][37][38][39][40]. These authors have pointed out that macroscopic quantities of coherently excited atoms may be employed to measure neutrino properties [36,39,41].…”

QED background against atomic neutrino process with initial spatial phase

“…As a proof-of-concept of the macrocoherent amplification, the QED two-photon process in which a photon substitutes for the neutrino pair of RENP, |e → |g + γ + γ, has been studied both theoretically [4] and experimentally [5,6,7,8]. In a series of experiments, the rate enhancement of O(10 18 ) was observed.…”

Frequency dependence of coherently amplified two-photon emission from hydrogen molecules

“…Recently, we succeeded in coherently amplifying the TPE process from the first vibrationally excited state of the electronic ground state (X 1 + g ) of parahydrogen molecules (p-H 2 ) [14,15], the energy diagram of which is shown in Fig. 1.…”