Articles you may be interested inEffect of V-defects on the performance deterioration of InGaN/GaN multiple-quantum-well light-emitting diodes with varying barrier layer thickness

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The strong light-matter interaction in ZnO-embedded microcavities has received great attention in recent years, due to its ability to generate the robust bosonic quasiparticles, exciton-polaritons, at or above room temperature. This review introduces the strong coupling effect in ZnO-based microcavities and describes the recent progress in this field. In addition, the report contains a systematic analysis of the room-temperature strong-coupling effects from relaxation to polariton lasing. The stable room temperature operation of polaritonic effects in a ZnO microcavity promises a wide range of practical applications in the future, such as ultra-low power consumption coherent light emitters in the ultraviolet region, polaritonic transport, and other fundamental of quantum optics in solid-state systems. Keywords: microcavity; polariton; strong coupling; ZnO INTRODUCTIONOver the past two decades, strong light-matter interactions in solidstate systems have garnered much attention for applications in novel photonics devices. The polariton is the key factor in the strong coupling phenomena: a new bosonic quasiparticle that is a hybrid between matter and light and exhibits promise for investigating various fascinating effects including dynamical Bose condensation, 1-4 superfluidity 5,6 and quantized vortices. 7-10 Semiconductor microcavities (MCs), which simultaneously offer good optical confinement with a small mode volume for the photonics portion and an excitonic layer for the matter portion of the strong coupling, are regarded as promising candidates for demonstrating and manipulating strong light-matter coupling in solid-state systems. 11 Because the semiconductor MCs undergo a strong coupling regime, the coupling rate between the bared exciton modes and the confined photon modes is faster than their dissipation rates. Compared with weakly coupled MCs, the rapid exchange rate in strongly coupled MCs renders the energy transfer between the excitons and photons reversible and reduces the possibility of energy dissipation through non-radiative channels, which results in a higher internal quantum efficiency. The new eigenstates generated from the strong exciton-photon coupling are called exciton-polaritons 12 and exhibit a relatively small effective mass compared with atomic hydrogen, tunable dispersion curves, and the bosonic statistics at low densities.Given the aforementioned properties, many phenomena have been extensively studied in polariton systems, including ultra-low threshold polariton lasing, 13 polariton parametric oscillation 14-17 and polaritonic circuits. 18 The matter characteristic of the polaritons allows them to scatter with electrons, phonons and polaritons, then to condense in the coherent ground state. The laser-like light emission from a coherent polariton ground state, the so-called polariton laser, does not require the population inversion condition required by conventional

A general and straightforward model was developed for the design of passively -switched lasers. With the secondthreshold criterion and using a numerically fitting procedure, the output pulse energy was expressed as an analytical function of the initial transmission of the saturable absorber and the reflectivity of the output coupler. An analytical expression for the optimal output reflectivity was also obtained for maximizing the output pulse energy of a passively -switched laser with a given initial transmission of the saturable absorber. Excellent agreement was studied between the present results and detailed theoretical computations. A Nd:YAG laser with Cr 4+ :YAG as a saturable absorber was performed to illustrate the use of the present model. Index Terms-Passively -switched laser, saturable absorber, solid-state laser, Cr 4+ :YAG.

We demonstrate experimentally that the near-field and far-field transverse patterns of a large aperture vertical cavity surface emitting laser (VCSEL) can be successfully interpreted as a two-dimensional (2D) billiard system. It is found that the near-field and far-field transverse patterns of a large aperture VCSEL evidently represent the coordinate-space and momentum-space wave functions of a 2D quantum billiard, respectively. The result of this paper suggests that large aperture VCSELs are potentially appropriate physical systems for the wave-function study in quantum problems.

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The connection between wave functions and classical periodic trajectories in a square billiard is analytically constructed by using the representation of SU(2) coherent states. The analytical function form is modified to show that the wave patterns can be apparently localized on the classical periodic trajectories by superposing a few nearly degenerate eigenfunctions. Based on the analogy between the Schrödinger and Helmholtz equations, the features of wave functions are experimentally studied from the transverse pattern formation in a laterally confined microcavity laser. The experimental transverse pattern in a square-shaped microcavity agrees very well with the constructed wave pattern concentrated along classical periodic orbits.