We present the study of many applications of electromagnetically induced transparency. From ultra-slow light to enhanced Brillouin scattering, the giant nonlinearity associated with this effect leads to many new and exciting experiments.
Electromagnetically induced transparency (EIT) is generation of a narrow window in which electromagnetic field absorption is inhibited. Experimentally, a probe tuned to a certain absorption wavelength is allowed to transmit through a gaseous vapor only in the presence of a second control laser. In other words, a probe is forbidden to cause an excitation from one energy level to another through coherent coupling with a third, intermediate energy level that creates an interference pathway. In this study, Brillouin scattering analogue of EIT is demonstrated using the two optical modes that are coupled through a phase matched acoustic mode. The coherent coupling of two energy levels is emulated by the acousto-optic interaction of Brillouin scattering. The probe phase response is analyzed to estimate BSIT's effect on the velocity of light pulse. As BSIT modifies the dispersion of light, it is understood as either slowing or advancing light propagation depending on the sign of the slope of the probe phase response. Lastly, the non-reciprocity of Brillouin scattering is theoretically considered. The non-reciprocity, or a break in time reversal symmetry, is a unique property of Brillouin scattering process due to the traveling surface acoustic wave which is used for phase matching the optical modes. Therefore, BSIT can be used for applications such as optical isolation while no other transparency systems can.
Summary form only given. Exciting observations of ultra-slow group velocities and very large nonlinearities in coherently driven atomic media open up interesting prospectives for nonlinear optical processes at low light levels. Recent experiments, for instance, demonstrated that very efficient nonlinear phenomena can be induced by laser fields of tiny energies. These developments stimulate the studies of ultimate efficiency limits for nonlinear optics based on electromagnetically induced transparency (EIT) as well as its possible applications for generation and manipulation of quantum entangled states of the light fields and matter. We describe a particular method that allows for two slow light fields of energies corresponding to that of a single photon to interact coherently.
Coherent nonlinear effects such as Electromagnetically Induced Transparency\n(EIT), Coherent Population Trapping (CPT), and Slow light are studied in thermal\nRb vapor by both continuous and pulsed laser fields. This work primarily includes\nthree parts: (I) mode-locked rubidium laser and its applications (II) enhanced coupling\nbetween optical and sound waves in the forward direction via ultra-slow light\n(III) optical steering via ultra-slow light in rubidium vapor.\nIn part(I), I describe the construction and study of a mode-locked rubidium laser\noperating at the Rb D1 line using an active mode-locking technique inside the laser\ncavity. The mode-locked laser field is used to observe coherent effects in a dense\nrubidium gas.\nIn part(II), I experimentally demonstrate enhanced acoustic-optic coupling that\noccurs when the velocity of sound is close to the group velocity of light. Dragging of\nthe light by effective motion of the gas in a Rb cell is the origin of enhanced coupling.\nGood agreement between theory and experiment is found.\nIn part(III), I experimentally demonstrate optical beam deflection in coherently\ndriven rubidium vapor due to the steep refraction index profile in the region of EIT.