The influence of quantum-well composition on the performance of quantum dot lasers using InAs-InGaAs dots-in-a-well (DWELL) structures

Liu, G.T.; Stintz, A.; Li, H.; Newell, T.C.; Gray, A.L.; Varangis, P.M.; Malloy, K.J.; Lester, L. F.

doi:10.1109/3.890268

Cited by 153 publications

(76 citation statements)

References 24 publications

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“…11 The DWELL layer is grown in the center of a GaAs waveguide ͑total waveguide thickness of 256 nm͒, which sits atop a 1.5 m thick Al 0.7 Ga 0.3 As buffer layer. The resulting peak of the ground state emission of the ensemble of QDs is located at = 1.35 m at room temperature.…”

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confidence: 99%

Single quantum dot spectroscopy using a fiber taper waveguide near-field optic

Srinivasan

Painter

Stintz

et al. 2007

Applied Physics Letters

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Photoluminescence spectroscopy of single InAs quantum dots at cryogenic temperatures ͑ϳ14 K͒ is performed using a micron-scale optical fiber taper waveguide as a near-field optic. A lower bound on the measured collection efficiency of quantum dot spontaneous emission into the fundamental guided mode of the fiber taper is estimated at 0.1%, and spatially resolved measurements with ϳ600 nm resolution are obtained by varying the taper position with respect to the sample and using the fiber taper for both the pump and collection channels. 4 have been implemented to improve the efficiency of light collection, while near-field scanning optical microscopy ͑NSOM͒ has been used to achieve sub-100 nm spatial resolution. 5 In this letter, we examine the use of optical fiber taper waveguides as a near-field optic for performing single QD spectroscopy. These micron-scale silica waveguides have been used in many studies of optical microcavities, beginning as an efficient coupler to silica microspheres. 6 More recently, we have shown that they can effectively probe the spatial and spectral properties of small mode volume ͑V eff ͒, high refractive index semiconductor cavities. 7 Other researchers have proposed 8,9 and realized their use as a collection tool for spontaneous emission from atomic vapors. 10 Here, we show that a fiber taper may be used to channel emission from single selfassembled QDs embedded in a semiconductor slab directly into a standard single-mode fiber with high efficiency ͑ϳ0.1% ͒, and to provide submicron spatial resolution of QDs.The QDs we study consist of a single layer of InAs QDs embedded in an In 0.15 Ga 0.85 As quantum well, a so-called dotin-a-well ͑DWELL͒ structure. 11 The DWELL layer is grown in the center of a GaAs waveguide ͑total waveguide thickness of 256 nm͒, which sits atop a 1.5 m thick Al 0.7 Ga 0.3 As buffer layer. The resulting peak of the ground state emission of the ensemble of QDs is located at = 1.35 m at room temperature. To limit the number of optically pumped QDs, microdisk cavities of diameter D =2 m were fabricated using electron beam lithography and a series of dry and wet etching steps. 12 Although the QDs physically reside in a microcavity, they are nonresonant with the cavity whispering gallery modes ͑WGMs͒. In other words, our primary interest here is general single QD spectroscopy through the fiber taper, without enhancement through interaction with the high quality factor ͑Q͒ microdisk WGMs. The samples were mounted in a continuous-flow liquid He cryostat that has been modified to allow sample probing with optical fiber tapers while being held at cryogenic temperatures ͑T ϳ 14 K͒, as described in detail in Ref. 13. The cryostat setup provides any combination of free-space and fiber taper pumping and collection ͓see Fig. 1͑a͒ for details͔.The inset of Fig. 1͑b͒ shows the emission spectrum from an ensemble of QDs in one of the microdisks. Here, the device is optically pumped through an objective lens at normal incidence ͑free-space pumping͒, with a spot size of 3 m and wa...

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Single quantum dot spectroscopy using a fiber taper waveguide near-field optic

Srinivasan

Painter

Stintz

et al. 2007

Applied Physics Letters

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“…Nondestructive material characterization, gain spectra measurements, and SLED device characteristics were all compared for various growth parameters. Seven InAs/InGaAs dot-in-a-well [16] layers separated by 50 nm of GaAs formed the active region of the QD SLED. Waveguiding was provided by doped Al 0.4 Ga 0.6 As cladding layers.…”

Section: Bandwidth Engineering In Qd Devicesmentioning

confidence: 99%

Quantum Dot Superluminescent Diodes for Optical Coherence Tomography: Device Engineering

Greenwood

Childs

Kennedy

et al. 2010

IEEE J. Select. Topics Quantum Electron.

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ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. Abstract-We present a 18 mW fiber-coupled single-mode superluminescent diode with 85 nm bandwidth for application in optical coherence tomography (OCT). First, we describe the effect of quantum dot (QD) growth temperature on optical spectrum and gain, highlighting the need for the optimization of epitaxy for broadband applications. Then, by incorporating this improved material into a multicontact device, we show how bandwidth and power can be controlled. We then go on to show how the spectral shape influences the autocorrelation function, which exhibits a coherence length of <11 µm, and relative noise is found to be 10 dB lower than that of a thermal source. Finally, we apply the optimum device to OCT of in vivo skin and show the improvement that can be made with higher power, wider bandwidth, and lower noise, respectively.Index Terms-Optical coherence tomography (OCT), quantum dot (QD), skin imaging, superluminescent diodes (SLEDs).

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“…In particular, the dots-in-a-well (DWELL) detector architecture pioneered at the University of New Mexico was used as a prototype in these studies 6,7 . The DWELL architecture is a hybrid structure in which InAs quantum dots are placed in an InGaAs quantum well.…”

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A monolithically integrated plasmonic infrared quantum dot camera

et al. 2011

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In the past few years, there has been increasing interest in surface plasmon-polaritons, as a result of the strong near-field enhancement of the electric fields at a metal-dielectric interface. Here we show the first demonstration of a monolithically integrated plasmonic focal plane array (FPA) in the mid-infrared region, using a metal with a two-dimensional hole array on top of an intersubband quantum-dots-in-a-well (DWELL) heterostructure FPA coupled to a read-out integrated circuit. Excellent infrared imagery was obtained with over a 160% increase in the ratio of the signal voltage (V s ) to the noise voltage (V n ) of the DWELL camera at the resonant wavelength of λ = 6.1 µm. This demonstration paves the way for the development of a new generation of pixel-level spectropolarimetric imagers, which will enable bio-inspired (for example, colour vision) infrared sensors with enhanced detectivity (D*) or higher operating temperatures.

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The influence of quantum-well composition on the performance of quantum dot lasers using InAs-InGaAs dots-in-a-well (DWELL) structures

Cited by 153 publications

References 24 publications

Single quantum dot spectroscopy using a fiber taper waveguide near-field optic

Single quantum dot spectroscopy using a fiber taper waveguide near-field optic

Quantum Dot Superluminescent Diodes for Optical Coherence Tomography: Device Engineering

A monolithically integrated plasmonic infrared quantum dot camera

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