Nanoscale light sources using metal cavities have been proposed to enable high integration density, efficient operation at low energy per bit and ultra-fast modulation, which would make them attractive for future low-power optical interconnects. For this application, such devices are required to be efficient, waveguide-coupled and integrated on a silicon substrate. We demonstrate a metal-cavity light-emitting diode coupled to a waveguide on silicon. The cavity consists of a metal-coated III–V semiconductor nanopillar which funnels a large fraction of spontaneous emission into the fundamental mode of an InP waveguide bonded to a silicon wafer showing full compatibility with membrane-on-Si photonic integration platforms. The device was characterized through a grating coupler and shows on-chip external quantum efficiency in the 10−4–10−2 range at tens of microamp current injection levels, which greatly exceeds the performance of any waveguide-coupled nanoscale light source integrated on silicon in this current range. Furthermore, direct modulation experiments reveal sub-nanosecond electro-optical response with the potential for multi gigabit per second modulation speeds.
Spectrometry is widely used for the characterization of materials, tissues, and gases, and the need for size and cost scaling is driving the development of mini and microspectrometers. While nanophotonic devices provide narrowband filtering that can be used for spectrometry, their practical application has been hampered by the difficulty of integrating tuning and read-out structures. Here, a nano-opto-electro-mechanical system is presented where the three functionalities of transduction, actuation, and detection are integrated, resulting in a high-resolution spectrometer with a micrometer-scale footprint. The system consists of an electromechanically tunable double-membrane photonic crystal cavity with an integrated quantum dot photodiode. Using this structure, we demonstrate a resonance modulation spectroscopy technique that provides subpicometer wavelength resolution. We show its application in the measurement of narrow gas absorption lines and in the interrogation of fiber Bragg gratings. We also explore its operation as displacement-to-photocurrent transducer, demonstrating optomechanical displacement sensing with integrated photocurrent read-out.
We demonstrate the control of the spontaneous emission rate of single InAs quantum dots embedded in a double-membrane photonic crystal cavity by the electromechanical tuning of the cavity resonance. Controlling the separation between the two membranes with an electrostatic field we obtain the real-time spectral alignment of the cavity mode to the excitonic line and we observe an enhancement of the spontaneous emission rate at resonance. The cavity has been tuned over 13 nm without shifting the exciton energies. A spontaneous emission enhancement of ≈ 4.5 has been achieved with a coupling efficiency of the dot to the mode β ≈ 92%.The coupling of a quantum emitter such as a quantum dot (QD) to a semiconductor photonic crystal cavity (PCC) has shown to be a promising method to realize single photon sources on a chip, 1 enabling applications in quantum key distribution and quantum photonic integrated circuits (QPIC). Two-dimensional PCCs are commonly used for this purpose due to the high achievable Q factors and small mode volumes. 2,3 The spontaneous emission rate of a two-level system is strongly affected by the local density of optical states provided by the surrounding electromagnetic resonator 4 and can be enhanced or suppressed depending on the spectral alignment between emitter and cavity. The spectral control of QDs has been already achieved using different methods such as temperature tuning, 5,6 Stark effect 7 and strain tuning, 8 while the control of the cavity resonance is more challenging. Cavity tuning has been obtained by controlled gas adsorption and local heating, 9,10 however this technique produces a permanent change in the QD emission energy preventing the separate control of QD and cavity. For QPIC applications, where many devices have to operate at the same wavelength, it is essential to tune each cavity independently over a wide wavelength range (> 10 nm), without affecting the QD emission wavelength and the Q factor. An attractive solution which fulfills all these requirements is provided by nano-opto-electro-mechanical structures (NOEMS). Previous works have demonstrated reconfigurable PCCs based on the electrostatic actuation of laterally coupled nanobeams, 11,12 slotted cavities 13 and twodimensional PCCs on double membranes. 14,15 The use of a vertically-coupled double-membrane is particularly convenient since it allows us to separate the QD layer from the actuation region in the vertical direction, removing any possible interaction between the electrostatic a) l.midolo@tue.nl field and the QDs. When two PCCs are brought at small distances (see inset Figure 1(a)) they couple evanescently, producing a splitting in a symmetric and an antisymmetric mode which shift in wavelength depending on the distance between the membranes. This technique has been demonstrated on InGaAsP/InP, 15 and has been shown not to affect the cavity Q. 14 However the operation at cryogenic temperatures (which is fundamental for QPIC applications) and the tuning to a single quantum dot have not yet been shown. In this ...
Optical read-out of motion is widely used in sensing applications. Recent developments in micro- and nano-optomechanical systems have given rise to on-chip mechanical sensing platforms, potentially leading to compact and integrated optical motion sensors. However, these systems typically exploit narrow spectral resonances and therefore require tuneable lasers with narrow linewidth and low spectral noise, which makes the integration of the read-out extremely challenging. Here, we report a step towards the practical application of nanomechanical sensors, by presenting a sensor with ultrawide (∼80 nm) optical bandwidth. It is based on a nanomechanical, three-dimensional directional coupler with integrated dual-channel waveguide photodiodes, and displays small displacement imprecision of only 45 fm/Hz1/2 as well as large dynamic range (>30 nm). The broad optical bandwidth releases the need for a tuneable laser and the on-chip photocurrent read-out replaces the external detector, opening the way to fully-integrated nanomechanical sensors.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.