5 research outputs found
Quantum superposition principle and generation of ultrashort optical pulses
We discuss the propagation of laser radiation through a medium of quantum
prepared {\Lambda}-type atoms in order to enhance the insight into the physics
of QS-PT generator suggested in Phys. Rev. A 80, 035801 (2009). We obtain
analytical results which give a qualitatively corerct description of the
outcoming series of ultrashort optical pulses and show that for the case of
alkali vapor medium QS-PT generation may be implemented under ordinary
experimental conditions
Train of high-power femtosecond pulses: Probe wave in a gas of prepared atoms
We present a new method for generating a regular train of ultrashort optical
pulses in a prepared two-level medium. The train develops from incident
monochromatic probe radiation travelling in a medium of atoms, which are in a
quantum mechanical superposition of dressed internal states. In the frame of
used linear theory for the probe radiation, the energy of individual pulses is
an exponentially growing function of atom density and of interaction cross
section. Pulse repetition rate is determined by the generalized Rabi frequency
and can be around 1 THz and greater. We also show that the terms, extra to the
dipole approximation, endow the gas by a new property: non-saturating
dependence of refractive index on the dressing monochromatic field intensity.
Contribution of these nonsaturating terms can be compatible with the main
dipole approximation in the wavelength region of about ten micrometers (the
range of CO_2 laser) or larger
Nondegenerate parametric down conversion in coherently prepared two-level atomic gas
We describe parametric down conversion process in a two-level atomic gas,
where the atoms are in a superposition state of relevant energy levels. This
superposition results in splitting of the phase matching condition into three
different conditions. Another, more important, peculiarity of the system under
discussion is the nonsaturability of amplification coefficients with increasing
pump wave intensity, under "sideband" generation conditions