Superluminescent diode with a broadband gain based on self-assembled InAs quantum dots and segmented contacts for an optical coherence tomography light source

Ozaki, Nobuhiko; Childs, David; Sarma, J.; Roberts, T.; Yasuda, Tatsuya; Shibata, Hiroshi; Ohsato, Hirotaka; Watanabe, Eiichiro; Ikeda, Naoki; Sugimoto, Yoshimasa; Hogg, R. A.

doi:10.1063/1.4942640

Cited by 25 publications

(18 citation statements)

References 32 publications

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“…We demonstrate a green SLED emitting at 526 nm based on the InGaN QW–QD tunneling structure. QDs are adopted as the active region as they are expected to realize a much broader optical spectrum than QWs and better temperature characteristics as well. − The structure of the SLED is shown in Figure a.…”

Section: Resultsmentioning

confidence: 99%

Abnormal Stranski–Krastanov Mode Growth of Green InGaN Quantum Dots: Morphology, Optical Properties, and Applications in Light-Emitting Devices

Wang

et al. 2018

ACS Appl. Mater. Interfaces

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Stranski–Krastanov (SK) growth mode is widely adopted for the self-assembled growth of semiconductor quantum dots (QDs), wherein a relatively large critical thickness is essential and a thick wetting layer (WL) is formed beneath the QD layer. In this paper, we report the metal organic vapor phase epitaxy of green InGaN QDs, employing a growth interruption method to decrease the critical thickness and improve the morphology of QDs. The QDs exhibit similar photoluminescence properties with those grown by conventional SK mode, implying the existence of a WL. We experimentally verify that the formation of QDs, whether based on the SK mode or the growth interruption method, conforms to the phase separation theory. However, the density of QDs grown by the interruption method exhibits abnormal dependence on the strain when a quantum well (QW) is inserted beneath the QD layer. Furthermore, the underlying QW not only influences the morphology of the QDs but also plays as a reservoir of electrons, which helps enhance the photoluminescence and the electroluminescence of the QDs. The method of QD growth with improved morphology and luminescence by introducing the QW–QD coupled nanostructure is universally applicable to similar material systems. Furthermore, a 550 nm green light-emitting diode (LED) and a 526 nm superluminescent LED based on the nanostructure are demonstrated.

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Section: Resultsmentioning

confidence: 99%

Abnormal Stranski–Krastanov Mode Growth of Green InGaN Quantum Dots: Morphology, Optical Properties, and Applications in Light-Emitting Devices

Wang

et al. 2018

ACS Appl. Mater. Interfaces

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“…Delay (u m) 15 Figure 6 plots the point spread functions (PSFs), calculated from the currents 1'-4' described in Figure 5a). By performing an inverse Fourier transform on the emission spectrum [24], the waveforms in Figure 6 can be produced from those in Figure 5a). This offers a more accurate estimate of the axial resolution than the formula for coherence length used to generate Figure 1, because that formula assumes the emission spectrum forms an ideal Gaussian.…”

Section: Device Modification and Resultsmentioning

confidence: 99%

Gallium nitride light sources for optical coherence tomography

et al. 2017

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The advent of optical coherence tomography (OCT) has permitted high-resolution, non-invasive, in vivo imaging of the eye, skin and other biological tissue. The axial resolution is limited by source bandwidth and central wavelength. With the growing demand for short wavelength imaging, super-continuum sources and non-linear fibre-based light sources have been demonstrated in tissue imaging applications exploiting the near-UV and visible spectrum. Whilst the potential has been identified of using gallium nitride devices due to relative maturity of laser technology, there have been limited reports on using such low cost, robust devices in imaging systems.A GaN super-luminescent light emitting diode (SLED) was first reported in 2009, using tilted facets to suppress lasing, with the focus since on high power, low speckle and relatively low bandwidth applications. In this paper we discuss a method of producing a GaN based broadband source, including a passive absorber to suppress lasing. The merits of this passive absorber are then discussed with regards to broad-bandwidth applications, rather than power applications. For the first time in GaN devices, the performance of the light sources developed are assessed though the point spread function (PSF) (which describes an imaging systems response to a point source), calculated from the emission spectra. We show a sub-7µm resolution is possible without the use of special epitaxial techniques, ultimately outlining the suitability of these short wavelength, broadband, GaN devices for use in OCT applications.

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“…By rotationally scanning, the label-free two-dimensional (2D) or three-dimensional (3D) structure image of the biological tissue can be obtained. Thus, the non-contact, non-invasive tomography of living tissue is realized [ 74 ]. Any physical property that alters the amplitude, phase and polarization properties of the sample light can be used to extract diagnostic information.…”

Section: Endomicroscopic Imaging Techniquesmentioning

confidence: 99%

Novel endoscopic optical diagnostic technologies in medical trial research: recent advancements and future prospects

Wang

2021

BioMed Eng OnLine

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Novel endoscopic biophotonic diagnostic technologies have the potential to non-invasively detect the interior of a hollow organ or cavity of the human body with subcellular resolution or to obtain biochemical information about tissue in real time. With the capability to visualize or analyze the diagnostic target in vivo, these techniques gradually developed as potential candidates to challenge histopathology which remains the gold standard for diagnosis. Consequently, many innovative endoscopic diagnostic techniques have succeeded in detection, characterization, and confirmation: the three critical steps for routine endoscopic diagnosis. In this review, we mainly summarize researches on emerging endoscopic optical diagnostic techniques, with emphasis on recent advances. We also introduce the fundamental principles and the development of those techniques and compare their characteristics. Especially, we shed light on the merit of novel endoscopic imaging technologies in medical research. For example, hyperspectral imaging and Raman spectroscopy provide direct molecular information, while optical coherence tomography and multi-photo endomicroscopy offer a more extensive detection range and excellent spatial–temporal resolution. Furthermore, we summarize the unexplored application fields of these endoscopic optical techniques in major hospital departments for biomedical researchers. Finally, we provide a brief overview of the future perspectives, as well as bottlenecks of those endoscopic optical diagnostic technologies. We believe all these efforts will enrich the diagnostic toolbox for endoscopists, enhance diagnostic efficiency, and reduce the rate of missed diagnosis and misdiagnosis.

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Superluminescent diode with a broadband gain based on self-assembled InAs quantum dots and segmented contacts for an optical coherence tomography light source

Cited by 25 publications

References 32 publications

Abnormal Stranski–Krastanov Mode Growth of Green InGaN Quantum Dots: Morphology, Optical Properties, and Applications in Light-Emitting Devices

Abnormal Stranski–Krastanov Mode Growth of Green InGaN Quantum Dots: Morphology, Optical Properties, and Applications in Light-Emitting Devices

Gallium nitride light sources for optical coherence tomography

Novel endoscopic optical diagnostic technologies in medical trial research: recent advancements and future prospects

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