Lasers based on coupled transitions with arbitrary polarization of radiation

Robert P. Lucht

Weston J. Sandle, M. W. Hamilton, R. J. Ballagh

This paper reports a steady-state theory for the polarization behaviour1 of the output of a ring optical cavity that contains a vapour of atoms with a driven J = 1 2 to J = 1 2 transition. The input laser radiation may have arbitrary polarization and detuning. We have extended a previously reported theory2 (which includes analytic results for zero detuning of the incident laser and zero magnetic field) to include detunings and magnetic fields.

I. P. Mazanko

N. B. Abraham, E. Arimondo, Maxi San Miguel

Armen D. Sargsyan, A. Tonoyan, David G. Sarkisyan

Abstract Magnetically induced Fg = 2 → Fe = 4 transitions corresponding to the 85Rb D2 line in the case of the σ+ circularly polarized radiation have been used for the first time to form optical dark resonances in strong magnetic fields up to 1 kG under electromagnetically induced transparency conditions. A 1.5-μm-thick cell filled with Rb atomic vapor has been used. The probabilities of two of five magnetically induced transitions, which are efficiently formed only with the σ+-polarized radiation, in the magnetic field range of 0.2–1 kG exceed the probabilities of “ordinary” atomic transitions. For this reason, it is appropriate to use them in Λ systems for the formation of the dark resonance. The following rule has been established: for the formation of the dark resonance in a Λ system with the use of the σ+-polarized probe radiation at the frequencies of magnetically induced transitions, the radiation of the coupling laser should also be σ+ polarized; the dark resonance is not formed if the radiation of the coupling laser is σ– polarized, which is confirmed by the calculated theoretical curve. A significant advantage of magnetically induced resonances for electromagnetically induced transparency compared to ordinary atomic transitions corresponding to the 85Rb D2 line has been demonstrated. The formation of dark resonances in strong magnetic fields, when their frequency is shifted by several gigahertzs, can be applied in practice.

S. G. Zeiger

An equation is derived for the density matrix of a gaseous ensemble in the field of a strong wave of circular or linear polarization. The competition of polarizations in a laser is discussed, and it is shown that for the 1--0 and 1--1 transitions, it is independent of the magnitude of the field, so that circular polarization will be generated at an arbitrary value of the gain. An equation is derived for the lasing intensity in a laser as a function of pumping, account being taken of the degeneracy of the energy levels. It is shown that for the 1--0 and 1--1 transitions, this equation reduces to a third-order equation for the quantity GAMMA/..gamma../sub 10/, where GAMMA is the width of the Bennett dip.