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Self-assembled quantum-dots (QDs) represent a distributed ensemble of zero dimensional structures with a near-singular density of states. Implemented as the active medium in a diode laser their unique properties lead to improved and often novel characteris ...
It was about 125 years ago that the light bulb was commercialized by Thomas Edison. No doubt a brilliant invention at the time, today its low power conversion efficiency is one of the reasons why lighting in the western world has such high energy consumpti ...
This thesis addresses general aspects of the operation of a coupled-cavity vertical surface-emitting laser (CC-VCSEL) which consists of two active cavities optically coupled and independently electrically pumped. The first two chapters of the thesis deal w ...
An electrically pumped VCSEL (10) and a method of its fabrication are presented. The VCSEL (10) comprises an active cavity material (14) sandwiched between top and bottom DBR stacks (12a, 12b), the top DBR (12b) having at least one n-semiconductor layer. T ...
We demonstrate edge-emitting lasers based on self-assembled InAs quantum dots (QDs) on GaAs substrates. The InAs QDs are embedded in an InGaAs quantum well (QW) to red-shift the lasing transition. The lasers emit at lambda=1.2 mum with threshold current de ...
Gallium Nitride (GaN) and its ternary alloys with aluminium and indium have met a growing interest in the last decade. These semiconductors have a large direct bandgap and can be doped with either silicon (Si) for n-type and magnesium (Mg) for p-type layer ...
Photonic crystal (PC) cavities enable localization of light into volumes (V) below a cubic optical wavelength (smaller than any other types of optical resonators) with high quality (Q) factors [1]. This permits a strong interaction of light and matter, whi ...
We present a detailed theoretical study of a vertical-cavity surface-emitting laser (VCSEL) with two optically coupled, active cavities. The study is based on a rate-equation model written for carriers and photons under steady-state conditions. The model a ...
We have studied the capabilities of chemical beam epitaxy (CBE) to produce high-gain media for long-wavelength (1.5 mu m) vertical cavity surface emitting lasers (VCSELs). Using a parameter pair of low growth temperature and small V/III ratio the integrati ...
We report the first successful use, to our knowledge, of InAsP quantum wells for 1.55 mu m wavelength laser emission: 5 quantum well InAsP/InGaAsP horizontal cavity lasers showed 88% internal efficiency, 1.6 cm(-1) losses per well, and 33 A/cm(2) transpare ...