Instability in degenerate two-photon running wave laser with detuning

Cun‐Zheng Ning, Hermann Haken

B. Zlatković, Aleksandar J. Krmpot, Nikola Šibalić +2 more

In this study we show the results for parametric non-degenerate four wave mixing (FWM) obtained using double lambda scheme at D1 line in hot potassium vapor. We have investigated the influence of one-photon detuning and two-photon detuning on the FWM gain. The laser frequency is locked at approximately 1GHz from the resonance 4S1/2 Fg=1 -< 4P1/2, using external reference cavity. The probe beam passes through acoustooptic modulator that enables controllable detuning around 460 MHz (ground state hyperfine splitting) in respect to the pump beam. The vacuum glass cell containing the potassium vapor was heated by hot air in order to achieve necessary concentration of atoms. The efficiency of FWM process is studied by measuring the gains of the conjugate beam the probe beam, simultaneously. The maximal gain was achieved for nonzero two photon detuning.

Eugenio Roldán, Germán J. de Valcárcel, Ramon A. Vilaseca

Eugenio Roldán, Germán J. de Valcárcel, Ramon A. Vilaseca +1 more

The stationary emission and stability of a three-level cascade laser in which two fields of different frequencies can be simultaneously amplified is investigated under conditions of cavity detuning. Different monomode and bimode solutions are found and analysed for the effects of different pitchfork and Hopf bifurcations. At moderate cavity detunings, features different from those observed in other classes of lasers are found, such as for instance a decrease in the instability threshold when detuning is introduced. Particular attention is paid to the case of resonance of the two-photon transition, which allows us to study the continuous evolution, when detuning is increased, of a resonant cascade laser towards a pure two-photon laser. In particular, this establishes the origin of some features which are characteristic of two-photon lasers.

Daniel J. Gauthier, Olivier Pfister, William J. Brown +1 more

Tao-Yi Fu, Murray Sargent

The Abrams-Lind formulation of degenerate four-wave phase conjugation is generalized to treat signal-pump detuning. The theory is an extension of two-wave grating-dip spectroscopy. We find that the reflection passband of phase conjugation is limited by the power-broadened bandwidth of the population difference, a width that can be very narrow. Unlike the running-wave saturator case, the signal absorption saturated by a standing wave shows no gain. This is due to the presence of appreciable amounts of unsaturated medium between spatial holes. We also generalize the degenerate three-wave mixing coefficients of Heer to include signal-pump detuning.