It has been shown that perfect photon absorption can occur in the linear excitation regime of cavity quantum electrodynamics (CQED), in which photons from two identical light fields coupled into two ends of the cavity are completely absorbed and result in excitation of the polariton state of the CQED system. The output light from the cavity is totally suppressed by the destructive interference and the polariton state can only decay incoherently back to the ground state. Here we analyze the perfect photon absorption and onset of optical bistability in the nonlinear regime of the CQED and show that the perfect photon absorption persists in the nonlinear regime of the CQED below the threshold of the optical bistability. Therefore the perfect photon absorption is a phenomenon that can be observed in both linear and nonlinear regimes of CQED. Furthermore, our study reveals for the first time that the optical bistability is influenced by the input-light interference and can be manipulated by varying the relative phase of the two input fields.

We propose and analyze a scheme for controlling coherent photon transmission and reflection in a cavity-quantum-electrodynamics (CQED) system consisting of an optical resonator coupled with three-level atoms coherently prepared by a control laser from free space. When the control laser is off and the cavity is excited by two identical light fields from two ends of the cavity, the two input light fields can be completely absorbed by the CQED system and the light energy is converted into the excitation of the polariton states, but no light can escape from the cavity. Two distinct cases of controlling the perfect photon absorption are analyzed: (a) when the control laser is tuned to the atomic resonance and creates electromagnetically induced transparency, the prefect photon absorption is suppressed and the input light fields are nearly completely transmitted through the cavity; (b) when the control laser is tuned to the polariton state resonance and inhibits the polariton state excitation, the perfect photon absorption is again suppressed and the input light fields are nearly completely reflected from the cavity. Thus, the CQED system can act as a perfect absorber or near perfect transmitter/reflector by simply turning off or on of the control laser. Such interference control of the coherent photon-atom interaction in the CQED system should be useful for a variety of applications in optical logical devices.

We present the first experimental observation of quantum fluctuation spectra in two coupled optical cavities with an injected squeezed vacuum light. The quadrature components of the reflected squeezed vacuum spectra are measured by phase-sensitive homodyne detector. The experimental results demonstrate coupled-resonator-induced transparency in the quantum regime, in which the electromagnetically-induced-transparency-like characteristic of the absorption and dispersion properties of the coupled optical cavities determines the line shape of the reflected quantum noise spectra.

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Autocollimators (ACs) are primarily used for two-dimension measurement with small angle. A three-dimensional AC (3D-AC) with a large measurement range and capable of 3D angle measurement is proposed based on a modified cube corner reflector (MCCR). The MCCR structure is designed by establishing the space coordinate vector relation model between AC and the reflectors with the rotation relation of Euler space. A 3D-AC angle measurement equation for MCCR dimension angle recognition is established. Experiments demonstrate that the proposed 3D-AC model can be used for 3D measurement. The measurement range of 3D-AC is 10°, and the uncertainty values for the one-dimensional and combined angle measurements are (57.10″, 55.25″, 40.43″) and (394.16″, 455.36″, 319.57″), respectively.

A broadband coherent perfect absorption (CPA) scheme consisting of an optical resonator coupled with three-level atoms excited by single cavity mode is proposed and analyzed. We show the output light field from the system is completely suppressed under specific conditions when the system is excited in linear and nonlinear regimes by two identical light fields from two ends of optical cavity. An analytical broadband CPA criterion for central and sideband excitations of cavity quantum electrodynamics (CQED) system is derived in linear regime. Moreover, we show the resonant excitation criterion for CPA is greatly extended in nonlinear regime. A new type of bistability behavior is found. The output field intensity and the bistability curve can be well tuned by dynamically adjusting system parameters. Our results demonstrate that the CPA is quite universal, and it should be useful in a variety of applications in optical logic and optical communication devices.

An all-optical controlled attenuation effect in an all-fiber system based on ionic liquid-filled photonic bandgap fiber (ILF-PBGF) is observed and demonstrated. The ILF-PBGF is formed by infusing a temperature-sensitive high-index ionic liquid into the cladding holes of the microstructured optical fiber. With the interactions between the controlling light and the highindex liquid columns, the bandgap drift of ILF-PBGF was observed, and an extinction ratio of about 8 dB was obtained at 1540 nm. Experimental investigations reveal that the attenuation is arose from the refractive index changes induced by thermal effect of the functional material.

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