ABSTRACT
We demonstrate and analyze the use of metamaterials featuring an analogue of electromagnetically induced transparency (EIT) in slow light technology. For most metamaterials, EIT-like effects suffer from intrinsic ohmic loss, and the metamaterial-based slow-light effect can only be tuned passively, which limits their application in slow light devices. We propose a hybrid metamaterial with a unit cell composed of a ring resonator formed from photoactive silicon (Si) and a rectangular bar formed from metallic silver (Ag). Based on an analogue of EIT in the designed hybrid metamaterial, we theoretically demonstrate an all-optical tunable slow-light effect in the telecommunication window. We successfully demonstrate the possibility of designing novel all-optical tunable chip-scale slow-light devices that could be used in optical buffering.
ABSTRACT
In this paper, we propose a microfiber-plane-grating composite optical waveguide (MPGCOW), which is formed by immobilizing a tapered microfiber on the surface of a plane grating with one defect, for gas refractive index (RI) sensing. Its optical properties and gas RI sensing properties are investigated by the finite difference time domain method. Results show that the MPGCOW has a photonic stop band and is very sensitive to the ambient gas RI variation. The largest gas RI sensing sensitivity of 486.67 nm/RIU and detection limit of 2×10-6 are obtained by immersing the structure in the mixture gas of N2 and He with various mixture ratios.
ABSTRACT
Based on the theoretical model of a microfiber double-knot resonator with a parallel structure, numerical simulations on the transmission spectrum, the phase, and the group time delay of the resonator as a function of wavelengths are given. We find that with this kind of resonator both slow light and fast light can be obtained at different resonant wavelengths. Experimentally, such a kind of microfiber resonator was fabricated successfully. The transmission spectrum of the fabricated resonator is well consistent with the theoretical simulation. A slow-light delay of about 38 ps and a fast-light advance of about 40 ps are demonstrated at different wavelengths, which might benefit the resonator to the applications in data delay lines, optical buffers, and optical memories.
ABSTRACT
In this paper, a compact slow-light microfiber coil resonator (MCR) is fabricated and the slow-light properties of it are analyzed and tested. Based on coupled-wave theory, a theoretical model for describing the slow-light propagation in the MCR is established. Experimentally, the MCR slow-light element is fabricated and its relative slow-light time delay is measured. The group velocity of the light pulse in the MCR slow-light element can be reduced to about 0.47c (c is the speed of light in vacuum) and the shape of the light pulse passing through the MCR is well preserved.
ABSTRACT
We propose a simple and compact slow-light element by use of an optical microcoil resonator (OMR) constituted by two microfiber coils. Based on the matrix exponential method, we solve the coupled-wave equations of the OMR with n turns of microfiber coils and obtain a general solution. Simulations indicate that a tunable slow-light propagation can be obtained by controlling the coupling coefficient between the two adjacent microfiber coils by means of regulating the voltage applied to the ferroelectric crystal. A slow-light time delay up to 62 ps with a bandwidth of 0.4 nm is performed at the wavelength around 1.5 µm.
