Nonstationary Light Emission by a Semi-Infinite Medium

Yu. N. Grachev, Alexander A. Kolokolov

Oleg N. Gadomsky, Irina V. Gadomskaya, S. V. Emelyanov

We investigate the boundary-value problem of nonresonant reflection and transmission of probe light wave passing through excited nonlinear semi-infinite medium of three- level atoms. The two lower levels are excited by intensive resonant stationary or nonstationary radiation to obtain the interference of atomic states. Some properties of near field effect in this problem are investigated taking into account retarded polarizing fields and the density-dependent near dipole-dipole interactions. We separate in our consideration three waves: the inversion wave and two polarization waves with corresponding nonlinear indices of refraction.

Ali A. Kamli, M. Babiker

The spontaneous-emission rate is evaluated for dipole emitters situated in the thin slab region between two semi-infinite one-dimensionally periodic photonic crystals, a situation reminiscent of planar cavity laser structures. It is pointed out that the long-wavelength electromagnetic fields supported by such complex structures can be directly quantized provided that the pair of semi-infinite photonic crystals are treated within the effective-medium approach, in which each photonic crystal is represented by a truncated uniaxial medium whose dielectric tensor components are determinable in terms of layer thicknesses and dielectric functions of the individual photonic crystal components. The spontaneous-emission rate is evaluated for a dipole emitter situated in the slab region, and oscillating at a frequency resonant with one of the modes that are localized within the slab and exponentially decaying within the photonic crystals. Both symmetric and asymmetric structures are discussed. Interesting features are predicted when the variations of the adjustable parameters are examined, including suppression and enhancement of the spontaneous rate.

Anatoly A. Afanas'ev, А. И. Урбанович

V. N. Lugovoǐ

Thorsten Peters, Shih-Wei Su, Yi‐Hsin Chen +3 more

We systematically study stationary light pulses formed in cold atomic media based on the effect of electromagnetically induced transparency (EIT) with counterpropagating laser fields. In contrast to hot media, the formation of stationary light in cold media is not straightforward. Detrimental coherences of high spatial frequencies can be excited which are naturally suppressed in hot media. We demonstrate numerically that these excitations prevent the formation of stationary light in cold media. We further present numerical and experimental results which show that these excitations can be dynamically suppressed in a medium of nonstationary atoms by reducing the width of the EIT transparency window below the typical Doppler shifts present in the medium. This provides an increased interaction time of the light pulses with the medium and enhances the efficiency of nonlinear optical interactions.