Cavity linewidth narrowing with dark-state polaritons

We present a quantum-theoretical treatment of cavity linewidth narrowing with intracavity electromagnetically induced transparency(EIT). By means of intracavity EIT, the photons in the cavity are in the form of cavity polaritons:bright-state polariton and dark-state polariton. Strong coupling of the bright-state polariton to the excited state induces an effect known as vacuum Rabi splitting, whereas the dark-state polariton decoupled from the excited state induces a narrow cavity transmission window. Our analysis would provide a quantum theory of linewidth narrowing with a quantum field pulse.     

Slow light with cavity electromagnetically induced transparency

We report an experimental observation of slow light propagation in cold Rb atoms exhibiting cavity electromagnetically induced transparency (EIT). The steep slope of the atomic dispersion manifested by EIT reduces the light group velocity. The cavity filtering and feedback further contribute to the slowdown and delay of the light pulse propagation. A combination of the cavity and the EIT atomic system significantly improves the performance of the slow light propagation. A propagation time delay of approximately 200 ns was observed in the cavity and Rb EIT system, which is approximately 70 times greater than the time delay calculated for the light pulse propagation through the same Rb EIT system without the cavity.     

EIT as a tool to observe dual wavelength operation of a semiconductor laser

We propose a simplified technique for dual wavelength operation of an extended cavity semiconductor laser, and its characterization using electromagnetically induced transparency (EIT). In this laser cavity scheme light beam is made converging before it incidences on the cavity grating. The converging angle of the beam creates two longitudinal oscillating modes of resonating cavity. Frequency separation between the longitudinal modes are measured with the help of beat frequency generation in a photodiode and creating pair of EIT spectra in Rb vapor. The pair of EIT dips that are generated due to dual wavelength of this laser (that is used as control laser) can be used to estimate frequency difference between the generated wavelengths. Width of EIT spectra can be used to estimate linewidth of individual wavelength components.     

Bio-organism detection in one-dimensional photonic crystals using electromagnetically induced transparency

We propose an optical sensor that allows site-selective detection of a refractive index change occurring due to any infiltration such as a bio-organism in a porous one-dimensional photonic crystal (PC). We use the electromagnetically induced transparency (EIT) to detect and locate the infiltration. With a localized change in the refractive index, the maximum of the peak EIT transmission shifts, which is determined by tuning the control field frequency. The strong dispersion and the narrowing of the absorption free response associated with EIT within the PC form the basis of such enhanced sensitivity.     

Cavity linewidth narrowing by means of electromagnetically induced transparency in Rb with a longitudinal magnetic field

We demonstrate a method for further reducing the cavity linewidth by the application of a small longitudinal magnetic field on the Rb cell. Because of the magnetic field multiple electromagnetically induced transparen- cies （EITs） are observed. The center EIT linewidth is measured as a function of the magnetic field. By utilizing the center EIT we narrow the cavity linewidth to 2 MHz which is half of the cavity linewidth without magnetic field.     

Quantum storage of single photons with unknown arrival time and pulse shapes

We present a scheme for the quantum storage of single photons using electromagnetically induced transparency (EIT) in a low-finesse optical cavity, assisted by state-selected spontaneous atomic emission. Mediated by the dark mode of cavity EIT, the destructive quantum interference between the cavity input-output channel and state-selected atomic spontaneous emission leads to strong absorption of single photons with unknown arrival time and pulse shapes. We discuss the application of this phenomenon to photon counting using stored light.     

Intracavity electromagnetically induced transparency

The effect of intracavity electromagnetically induced transparency (EIT) on the properties of optical resonators and active laser devices is discussed theoretically. Pronounced frequency pulling and cavity-linewidth narrowing are predicted. The EIT effect can be used to reduce classical and quantum-phase noise of the beat note of an optical oscillator substantially. Fundamental limits of this stabilization mechanism as well as its potential application to high-resolution spectroscopy are discussed.     

Observation of electromagnetically induced transparency in a ring cavity

A scheme to observe Electromagnetically induced transparency (EIT) in an optomechanical system is proposed in the current paper. We treat a narrowband squeezed field as the weak probe field. We find that EIT dips exist in the output field. Moreover, the dependence of the EIT dips on the effective cavity detuning Δ and the input power ζ are explored. We show that the width of the EIT dips can be controlled by the parameters ξ and the detuning Δ.     

Absorptive reduction and width narrowing in Λ-type atoms confined between two dielectric walls

This paper investigates the absorptive reduction and the width narrowing of electromagnetically induced transparency （EIT） in a thin vapour film of A-type atoms confined between two dielectric walls whose thickness is comparable with the wavelength of the probe field. The absorptive lines of the weak probe field exhibit strong reductions and very narrow EIT dips, which mainly results from the velocity slow-down effects and transient behaviour of atoms in a confined system. It is also shown that the lines are modified by the strength of the coupling field and the ratio of L/λ, with L the film thickness and λthe wavelength of the probe field. A simple robust recipe for EIT in a thin medium is achievable in experiment.     

The Image Property in an EIT Information Transfer System

We focus on the study of the transferred image property in an electromagnetically induced transparency(EIT)system.In our experiment,a triple-peak image is effectively transferred from a coupling beam to a signal beam based on the EIT effect.It is found that the transferred image intensity profile of the signal beam is the same as that of the coupling beam while not in phase.Furthermore,the propagation property of the transferred image is studied.Due to the narrowing effect,the transferred image keeps narrowing and maintains the shape well within a certain distance outside of the medium.Our experimental results are in excellent agreement with the theoretical analysis.     

Chaos in an electromagnetically induced transparent medium inside an optical cavity

We theoretically predict and experimentally demonstrate chaotic behaviors in a system comprising of three-level atoms inside an optical ring cavity. This electromagnetically induced transparency (EIT) system is driven to chaos through period-doubling route by reducing the frequency detuning of the coupling laser beam. The chaos occurs in a different parametric regime as previously predicted and is believed to be caused by the enhanced dispersion and nonlinearity due to induced atomic coherence in such EIT system.     

Electromagnetically induced transparency of single Λ-type three-level atom in high-finesse optical cavity

We study the features of the electromagnetically induced transparency (EIT) in a single Λ-type three-level atom placed in a high finesse cavity under the action of a coupling laser and a probe laser. Our calculations show that three transparency windows appear when the pump strength is big enough. It can be explained by the residual pump in the cavity resulting mostly in the energy splitting. Level |3〉is split into four slightly different energy levels. An interference takes place between excitation pathways. Furthermore, it is also shown that the frequencies of the EIT windows can be tuned by changing the coupling field detuning Δ₂ and the reflection profile is very sensitive to the cavity field detuning Δ_c.     

包含三能级原子环形腔的动态非稳与混沌过渡

在包含三能级原子的环形腔的输出光场中，观察到了由电磁感应透明（EIT）效应导致的动态非稳及混沌．该动态非稳及向混沌的过渡可以通过耦合光场而加以很好地控制．同时，由三能级EIT导致的原子相干改变了系统的吸收、色散及非线性效应，从而极大地增强了系统的动态非稳和混沌过渡特性．建立了一个理论模型来定量地解释观察到的现象．     

Coherent effect of triple-resonant optical parametric amplification inside a cavity with injection of a squeezed vacuum field

In theory, we study the quantum tluctuatlons ot tlae suDllarmonlc renecteu nela Irom a ulplc-rc~ulltUtt IdU~ClIClatC optical parametric amplifier （OPA） inside an optical cavity. We discuss two cases, where the linewidth of the harmonic field is either much narrower or broader than the subharmonic field. Since an electromagnetically-induced-transparency （EIT）-like effect can be simulated in a triple-resonant OPA, the output spectra from a triple-resonant OPA with a squeezed vacuum input may simulate the phenomenon of the response of an EIT medium for squeezed states. This scheme can be implemented with present experimental setups.     

Spectral narrowing of a dye laser oscillation using an intracavity vapor prism

A new method for narrowing the oscillation spectrum of a broad-band dye laser is reported in this paper. The narrowing is achieved by a vapor prism placed inside the laser cavity, which is based on an anomalous dispersion of the atomic vapor so that the narrowing effect occurs only in the vicinity of the absorption line. Using a sodium vapor prism inside a Rhodamine 6G dye laser cavity, an oscillation linewidth less than 0.01 nm was attained at a sodium temperature of 320°C.     

Theoretical Investigation of Light Transmission in a Slab Cavity via Kerr Nonlinearity of Carbon Nanotube Quantum Dot Nanostructure

In this paper, we discuss the transmission properties of weak probe laser field propagate through slab cavity with defect layer of carbon-nanotube quantum dot (CNT-QD) nanostructure. We show that due to spin-orbit coupling, the double electromagnetically induced transparency (EIT) windows appear and the giant Kerr nonlinearity of the intracavity medium can lead to manipulating of transmission coefficient of weak probe light. The thickness effect of defect layer medium has also been analyzed on transmission properties of probe laser field. Our proposed model may be useful for integrated photonics devices based on CNT-QD for applications in all-optical systems which require multiple EIT effect.     

Cavity linewidth narrowing by voltage-controlled induced transparency in asymmetry quantum dot molecules

We theoretically investigate cavity-linewidth narrowing by means of voltage-controlled induced transparency in asymmetric double quantum dot system. The impact of voltage on frequency pulling and cavity linewidth narrowing is discussed. The linewidth and position of the cavity transmission can be engineered by the bias voltage. The scheme may be useful in designing novel optoelectronic devices.     

Electromagnetically induced transparency-like effect in the degenerate triple-resonant optical parametric amplifier

We investigate experimentally the absorptive and dispersive properties of the triple-resonant optical parametric amplifier (OPA) for the degenerate subharmonic field. In the experiment the subharmonic field is utilized as the probe field and the harmonic wave as the pump field. We demonstrate that the electromagnetically induced transparency (EIT)-like effect can be simulated in the triple-resonant OPA when the cavity linewidth for the harmonic wave is narrower than that for the subharmonic field. However, this phenomenon cannot be observed in a double-resonant OPA. The narrow transparency window appears in the reflected field. Especially in the measured dispersive spectra of the triple-resonant OPA, a very steep variation of the dispersive profile of the subharmonic field is observed, which can result in a slow light as that observed in an atomic EIT medium.     

Pattern formation in a cavity longer than the coherence length of the light in it

We study, theoretically and experimentally, the evolution of patterns in a passive nonlinear cavity that is longer than the coherence length of the light circulating in it. The patterns exhibit spatial line narrowing as the feedback is increased, resembling the line narrowing in lasers.     

Optomechanical dynamics in detuned whispering-gallery modes cavity

The dynamics of a microresonator in detuned whispering-gallery modes (WGM) cavity opto-mechanical system are investigated by the quantum Langevin equation. A WGM cavity coupling to two parallel waveguides is devised to study the transmission and reflection of this system. In single mode WGM cavity, without optomechanical coupling, both the transmission and reflection of the cavity present a Lorentzian dip and peak. When the coupling between the cavity mode and mechanical mode is considered, the transmission and reflection of the optomechanical cavity show “W” and “M” shape mode splitting. Moreover, under the action of a controlling and a probe laser, the output field at the probe frequency presents electromagnetically induced transparency (EIT)-like spectrum in the system. We give the physical origin of EIT-like and the pump-probe response for the WGM shares all the features of the Λ system in atoms. Further, due to backscattering, the two traveling waves in WGM are coupled with a rate γ. The transmission and reflection of the optomechanical cavity display three modes splitting in the spectra with optomechanical coupling between the two cavity modes and the mechanical mode.