Article
Ultrasmall microdisk and microring lasers based on InAs/InGaAs/GaAs quantum dots
Ultrasmall microring and microdisk lasers with an asymmetric air/GaAs/Al0.98Ga0.02As waveguide and an active region based on InAs/InGaAs/GaAs quantum dots emitting around 1.3 μm were fabricated and studied. The diameter D of the microrings and microdisks was either 2 or 1.5 μm, and the inner diameter d of the microrings varied from 20% to 70% of the outer diameter D. The microring with D = 2 μm and d = 0.8 μm demonstrated a threshold pump power as low as 1.8 μW at room temperature. Lasing was observed up to 100°C owing to the use of quantum dots providing high confinement energy both for electrons and holes. Tuning spectral positions of the whispering gallery modes via changing the inner diameters of the microrings was demonstrated.
The conference was held in the form of lectures by leading scientists, oral and poster presentations of young scientists and students of physical specialties, as well as leaders of innovative structures for the purpose of mutual acquaintance with the new results of fundamental research on a wide range of areas in physics, the prospects and challenges in the expansion of relations between science , education and high technologies. SECTION (heads): I. LASERS (Fundam. Probl., Computer ...) (prof. A.A.Ionin) II. OPTICS (quant., And nano materials and new sources) (d.f.m.n.A.V.Masalov) III. Solid state physics, INCLUDING Nanostructures ELEM. BASE UNIT (Corresponding Member of RAS N.N.Sibeldin) IV. Nuclear physics, high energy physics (prof. O.D.Dalkarov, Head: Prof. V.A.Ryabov) V. PLASMA PHYSICS and particle beams (Head: Prof. A.V.Agafonov) VI. Astrophysics (Head: Prof. S.A.Bogachev) VII. PHYSICS IN THE MODERN INSTRUMENT AND TECHNOLOGY (prof. V.N.Nevolin)
The paper discusses the methods and technologies used in the development of special software for control panel of shipboard laser complex (SLC) and a set of software simulators information flows generated by the equipment SLC interaction with the control panel.
p-i-n photodiodes comprising dense arrays of InGaAs quantum dots (referred to as quantum well-dots) were fabricated, and the basic physical processes affecting their highspeed performance were studied for the first time by measuring the frequency response under illumination with photons absorbed either in the quantum well-dots (905-nm illumination) or mainly in GaAs layers (860-nm illumination). A GaAs p-i-n photodiode of similar design was also measured for comparison. A maximum −3 dB bandwidth of 8.2 GHz was measured for the 905-nm light illumination, and maximum internal −3 dB bandwidth of 12.5 GHz was estimated taking into account the effect of RC-parasitic by the equivalent circuit model. It was found that the internal response is mainly controlled by the carrier drift time in the depletion region; this process can be characterized by a field-dependent effective velocity of charge carriers in the layered heterostructure, which is approximately half the saturation velocity in GaAs. The carrier escape from the InGaAs quantum well-dots was found to has less effect; the escape time was estimated to be 12–17 ps depending on the reverse-bias voltage applied.
The rate equations are used to analyze the characteristics of a tandem consisting of a laser diode and a semiconductor optical amplifier made of a single heterostructure with quantum dots. The optimal value of the current distribution coefficient the amplifier and the laser, as well as the optimal resonator length that provides the highest output power of the tandem were determined. It is shown that the use of the tandem allows, at the same total consumed current, to significantly (more than 4 times for 1A) increase the power emitted through the groundstate optical transition in comparison with that achievable with a laser diode solely being limited by the onset of lasing through an excited-state optical transition.
In Proceedings of the conference participants are presented on the following topics: 1) Lasers and Optics 2) Solid State Physics 3) Nuclear Physics 4) The generation and use of X-rays 5) Plasma Physics and particle beams 6) Astrophysics
CLEO®/Europe-EQEC targets university and industry scientists and researchers as well as students and graduates. The conference series has established a strong tradition as the largest, most comprehensive and prestigious gathering of optics and photonics researchers and engineers in Europe. With technical co-sponsorship provided by the European Physical Society (EPS), the Institute of Electrical and Electronics Engineers (IEEE) Photonics Society, and the Optical Society (OSA), CLEO®/Europe and EQEC have a strong international presence in the complementary research areas of laser science, photonics and quantum electronics.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
Let G be a semisimple algebraic group whose decomposition into the product of simple components does not contain simple groups of type A, and P⊆G be a parabolic subgroup. Extending the results of Popov [7], we enumerate all triples (G, P, n) such that (a) there exists an open G-orbit on the multiple flag variety G/P × G/P × . . . × G/P (n factors), (b) the number of G-orbits on the multiple flag variety is finite.
I give the explicit formula for the (set-theoretical) system of Resultants of m+1 homogeneous polynomials in n+1 variables