• Korean Journal of Optics and Photonics
• /
• v.13 no.5
• /
• pp.449-454
• /
• 2002

We have studied the effects of incoherent pumping on EIA at the transition between the $F_g=2$ ground state and the $F_e=3$ excited state in $^{85}Rb\;D_1$-line. Generally, the studies about EIA have been done in the cycling transition, where the population has no loss to other states. In the case of EIA by using the $^{85}Rb\;D_1$ transition line, the population is transferred to the other hyperfine state due to optical pumping. We incoherently pumped the atoms from $F_g=3\;to\;F_g=2$ with the pumping beam, which is resonant at the transition from $F_g=3\;to\;F_g=2$. We were able to observe the effects of incoherent pumping depending on the power and the polarization of the pumping beam.

• Korean Journal of Optics and Photonics
• /
• v.14 no.5
• /
• pp.483-490
• /
• 2003

We have analyzed theoretically optical pulse propagation in a coherent atomic medium for amplification without inversion (AWI), which is achieved by adding incoherent optical pumping to a typical EIT system. In order to explain experimental results [Kim et al., J. Phys. B, 36, 2671(2003)] to control the group velocity of the optical pulse by changing pumping power, we established a 5-level atomic system and applied density matrix equations. This AWI model system is different from previous AWI systems from the viewpoint of using two levels for incoherent optical pumping isolated optically from the EIT (electromagentically induced transparency) system so that more atoms can participate in pulse speed control. We have found that population transfer by collisions between ground states plays a decisive role for efficient AWI, and more atoms are effective for slowing the pulse. Our numerical results are in good agreement qualitatively with experimental results.

• Korean Journal of Optics and Photonics
• /
• v.11 no.5
• /
• pp.301-305
• /
• 2000

The electromagnetically induced absorpTIon (EIA) in the transition line, F=4$\longrightarrow$F'=5, of Cs $D_2$ line was lnveslIgaled. We observed the large increase in atomic absorption due to cohelent interaction with two resonanllaser fields. The requuements of EIA in the Cs atoms were investigated experimentally. The magnitude of EIA signal dependIng on both laser jinewidth and the intensity of coupling laser was measured. Also we are able to observe the amplified absorption signal by incoherent optical pumping of atoms into the closed system.system.