Multiphoton Destructive Interference Research Articles

High-precision two-dimensional atom localization from four-wave mixing in a double-Λ four-level atomic system

We propose a scheme for high-precision two-dimensional (2D) atom localization via the four-wave mixing (FWM) in a four-level double- atomic system. Due to the position-dependent atom-field interaction, the 2D position information of the atoms can be directly determined by the measurement of the normalized light intensity of output FWM-generated field. We further show that, when the position-dependent generated FWM field has become sufficiently intense, efficient back-coupling to the FWM generating state becomes important. This back-coupling pathway leads to competitive multiphoton destructive interference of the FWM generating state by three supplied and one internally generated fields. We find that the precision of 2D atom localization can be improved significantly by the multiphoton destructive interference and depends sensitively on the frequency detunings and the pump field intensity. Interestingly enough, we show that adjusting the frequency detunings and the pump field intensity can modify significantly the FWM efficiency, and consequently lead to a redistribution of the atoms. As a result, the atom can be localized in one of four quadrants with holding the precision of atom localization.

Phase control of highly efficient four-wave mixing in a six-level tripod atomic system.

We investigate theoretically an enhancement of four-wave mixing (FWM) process in phase-dependent double electromagnetically induced transparency (EIT) six-level atomic media. It is shown, owing to the multiphoton destructive interference, that the conversion efficiency of FWM can be enhanced by manipulating the relative phase of the applied fields in this ultraslow propagation regime. Moreover, we also find that the conversion efficiency is amplified with the presence of the microwave field in comparison with the previous six-level scheme [Phys. Rev. A76, 043809 (2007)PLRAAN1050-294710.1103/PhysRevA.76.043809].

Effective hyper-Raman scattering via inhibiting electromagnetically induced transparency in monolayer graphene under an external magnetic field

We propose and analyze an effective scheme to generate hyper-Raman scattering via inhibiting electromagnetically induced transparency (EIT) in a monolayer graphene under a magnetic field. By solving the Schrödinger-Maxwell formalism, we derive explicitly analytical expressions for linear susceptibility, nonlinear susceptibility, and generated Raman electric field under the steady-state condition. Based on dressed-state theory, our results show a competition between EIT and hyper-Raman scattering, and the hyper-Raman process is totally dominant when multiphoton destructive interference is completely suppressed.

CONTROLLABLE FOUR-WAVE MIXING IN A MICROWAVE-DRIVEN SIX-LEVEL ATOMIC SYSTEM

A scheme of high-efficiency four-wave mixing (FWM) is discussed in the case of an atomic medium in a six-level configuration via two electromagnetically induced transparencies (EIT) and a multiphoton destructive interference induced transparency. By adjusting the intensity of the microwave field, an increase of several orders in the conversion efficiency of FWM can be obtained. Our scheme may provide new possibilities for technological applications such as nonlinear spectroscopy at very low light intensity, quantum single-photon nonlinear optics and quantum information science.

Highly efficient four-wave mixing in a coherent six-level system in ultraslow propagation regime

We propose a scheme to obtain a highly efficient four-wave mixing (FWM) in a coherent six-level tripod system by using a double-dark resonance and multiphoton destructive interference induced transparency. We show both analytically and numerically that the optical-wave mixing in such a system with a pump wave and an internally generated FWM wave mediated by electromagnetically induced transparency and hence propagating with matched ultraslow group velocities can result in a significant enhancement of FWM conversion efficiency. This interesting scheme may be used to generate coherent short-wavelength radiation in dense optical media with very low pump-wave intensity.

Achieving induced transparency with one- and three-photon destructive interference in a two-mode, three-level, double-Λsystem

We show that in a two-mode, three-level, double-{lambda} system an efficient multiphoton destructive interference involving one- and three-photon pumping pathways occurs, leading to a unique type of induced transparency. Unlike the conventional electromagnetically induced transparency achieved with a three-state {lambda} system, the induced transparency is critically dependent upon two distinctive relaxation processes involving the production and propagation of an internally generated field. When a two-mode probe field is injected under suitable conditions, we show that the two probe pulses, after a characteristic propagation distance, evolve into a pair of temporal, amplitude, and group velocity matched pulse, traveling loss free in a highly dispersive medium.

Efficient multiwave mixing in the ultraslow propagation regime and the role of multiphoton quantum destructive interference

We analyze a lifetime-broadened four-state four-wave-mixing (FWM) scheme in the ultraslow propagation regime and show that the generated FWM field can acquire the same group velocity and pulse shape as those of an ultraslow pump field. We show that a new type of induced transparency resulted from multiphoton destructive interference that significantly reduced the pump field loss. Such induced transparency based on multphoton destructive interference may have important applications in other nonlinear optical processes.

Inelastic wave mixing and multi-photon destructive interference based induced transparency in coherently prepared media

We consider a multi-level medium initially prepared with a coherent superposition of two initial levels that are not directly dipole-coupled. We study the production of multi-wave mixing in the coherent medium, where the process begins on one and terminates on the other of the two prepared levels. We find that a new type of wave mixing field can be efficiently generated in such a system with characteristics of both conventional four-wave mixing and stimulated hyper-Raman emission. We also show that two multi-photon destructive interferences build up simultaneously, leading to simultaneous reduction of the attenuation of the pump and wave-mixing fields. As a consequence a pair of ultra slow, temporally and group-velocity matched pump and wave-mixing fields can be generated. This type of multi-photon induced transparency and its consequences are qualitatively different from the conventional EIT where the destructive interference occurs between two single photon channels.

Observation of broadband forward hyper-Raman emission with high intensity focused laser beams

We show that the well known multiphoton destructive interference, which leads to hyper-Raman gain suppression in the weak pumping regime, no longer occurs under strong pumping conditions. In contrast to the weak pumping case, where no forward hyper-Raman can be observed and strong backward hyper-Raman occurs, forward hyper-Raman emission is found to be much stronger under strong pumping conditions. The emission spectrum acquires new characteristics due to the ac Stark effect introduced by the strong laser field. The frequency spectrum of the forward hyper-Raman is no longer determined by the laser bandwidth, instead a continuum of forward hyper-Raman emission is observed with the width being determined by the peak power density. We will present here a comparison between strong and weak pumping regimes.

Gain suppression involving both stimulated Raman and hyper-Raman photons in two-step stimulated emissions

We show that multiphoton destructive interference leading to gain suppression can be produced even when two different step-wise stimulated emissions, such as stimulated Raman and hyper-Raman emissions, are included in the interference loop.