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Nonlinear Photonic Crystals
Published in Costantino De Angelis, Giuseppe Leo, Dragomir N. Neshev, Nonlinear Meta-Optics, 2020
P. Colman, S. Combrié, A. De Rossi, A. Martin, G. Moille
It has to be noted that the enhancement holds for a CW excitation as well, although in this case the definition of the propagation speed is problematic. The confusion arises from interpreting the slow-light enhancement of the light-matter interaction, hence of the nonlinearity, as being due to an increased time of light-matter interaction. A possibly better interpretation is formulated in terms of the Local Density of the Optical States (L-DOS). In cavity electro-dynamics, this effect is known as the Purcell effect. The Purcell formula can be extended to open geometry systems (waveguides) and exhibits then a contribution from the first derivative of the band diagram ∂ωk, which we have precisely defined as being the group velocity. That is why we differentiate structured slow light from material slow-light where the L-DOS remain unchanged. As a result, slow-light enhancement of nonlinearity does not exist in latter system. Thus, the slow-down factor S=ng/n in a structured waveguide can be interpreted to be the counterpart of the quality factor Q in a cavity [107].
Cavity–Matter Interaction in Weak- and Strong-Coupling Regime: From White OLEDs to Organic Polariton Lasers
Published in Marco Anni, Sandro Lattante, Organic Lasers, 2018
Marco Mazzeo, Fabrizio Mariano, Armando Genco, Claudia Triolo, Salvatore Patanè
In the weak-coupling regime, the Purcell effect may allow for the management of light distribution and the increase in overall efficiency. The microcavities can be integrated in an electrical architecture that simultaneously would allow for light confinement and charge carrier injection. As we will show, microcavity resonators can be theoretically exploited to realize electrically injected organic lasers. Nevertheless, despite the Purcell effect, the amount of current density that must be employed to reach the lasing threshold is behind the thermal capacity of organic lasers. For this reason, organic lasers by electrical injection are still a dream. The strong-coupling regime may help to reach this technological target. Organic polaritons, the hybrid particles between photons and excitons emerging from the strong-coupling interaction, are able to undergo the quantum phase transition of Bose–Einstein condensation (BEC) at room temperature. From this state, they can emit light coherently, like a standard laser, but from spontaneous emission decay. Therefore, organic microcavities in the strong-coupling regime are very promising for the realization of low-threshold electrically injected organic polariton lasers.
Single-Photon Sources
Published in Joachim Piprek, Handbook of Optoelectronic Device Modeling and Simulation, 2017
Niels Gregersen, Dara P. S. McCutcheon, Jesper Mørk
The first strategy proposed to improve the efficiency and control the light emission was based on cavity QED, where the QD was placed in a microcavity (Gérard, 2003). Here the Purcell effect ensures a preferential single-photon emission from the QD into the cavity mode. This preferential coupling requires a careful spectral alignment between the QD emission line and the cavity line as discussed in detail in Section 46.3. This approach has led to efficiencies of 0.8 (Gazzano et al., 2013) as well as an indistinguishability of 0.99 from the micropillar cavity SPS (Ding et al., 2016; Somaschi et al., 2016), representing the current state of the art in highly efficient sources of indistinguishable photons.
FDTD Based Simulation of Light Extraction in OLED using Triangular Band Structure
Published in IETE Journal of Research, 2023
P. Santhoshini, K. HelenPrabha
This is addressed by the dipole cloud analysis object [9]. It is also important for the dipole source to be sufficiently away from the simulation region (the grey box defining the object should not meet the simulation region). Otherwise, the intended symmetry of the unit cells can be disrupted. For example, in the FCC3D case, the number of mesh cells in each direction should be divisible by 3 to ensure that each triangle in the simulation region is meshed the same way. This can be done by rotating the unit cells. It must be confirmed before running the simulation and the mesh should be adjusted, so each unit cell included in the simulation region is meshed in exactly the same way i.e. the mesh lines fall at the same positions relative to the structure for each unit cell. Due to the strong plasmonic absorption [10] of emitters, Purcell effect introduces large decay differences. Emission rate reduced emitter quantum efficiency which decreases the lifetime splitting because the non-radiative decays will progressively prevail against the radiative ones, thus reducing the differences between parallel and perpendicular decay rates.
Multistability and Fano resonances in a hybrid optomechanical photonic crystal microcavity
Published in Journal of Modern Optics, 2021
Sajia Yeasmin, Surabhi Yadav, Aranya B. Bhattacherjee, Souri Banerjee
Cavity quantum electrodynamics (C-QED) explores the physics of enhanced interaction between photons and quantum emitters confined in a small volume [1,2]. Coherently controlling the spontaneous emission of the quantum emission of the quantum emitter has been one of the key advantages of C-QED [3,4] and is now called the Purcell effect [5]. In the strong coupling regime, the reversible interaction between quantum emitters and photons lead to a remarkable quantum phenomenon called the vacuum Rabi splitting (VRS) [6], which has been observed experimentally in different C-QED systems [7–11]. The cavity mode decay rate, non-resonant decay rate and emitter-photon coupling strength are the parameters which define three different characteristic time-scale for the dynamics of the emitter-photon system to be classified as either weak or strong coupling [12–16]. In a recent theoretical study, auxiliary-cavity-assisted VRS in a hybrid photonic crystal (PhC) nano-cavity embedded with a quantum dot (QD), has been demonstrated. The results indicated that the auxiliary cavity played a crucial role to control the dynamics of the system [17].