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Ultrasound sensors such as piezoelectric transducers and CMUTs are successfully used for medical imaging. However, especially wiring of individual elements is difficult in the fabrication of small piezoelectric arrays, used in, e.g. the field of intravascular imaging. As an alternative, we designed a novel type of ultrasound receiver based on silicon-on-insulator technology. This receiver contains...
We investigate the radiation of an optical leaky-wave antenna embedded in a Fabry-Pérot resonator (FPR), resonating in the direction of the guided leaky wave. Leaky-wave radiation is achieved via the generation of a −1 Floquet harmonic in a dielectric waveguide due to the inclusion of a periodic set of perturbations. The FPR is formed by confining the dielectric waveguide and the leaky-wave section...
We show that broad periodic waveguides operating at the Littrow regime can form series of modes with a negative dispersion in their spacing (dFSR / dω > 0, FSR = Free Spectral Range), thanks to samples with extended range. We provide an analysis of this experimental FSR based on a nearly analytical consideration. For frequency combs, a uniform FSR (dispersion free) can be attained at any desirable...
Electric and magnetic dipolar and quadrupolar Mie resonances in high index dielectric particles exhibit high quality factor that compensate their low field confinement compared to the plasmon resonances of metallic particles [1]. In a host matrix of refractive index n = 1.45, and when a dipolar electric or magnetic emitter is placed at the center of a dimer of Si spheres, we obtain enhancement factors...
Micro-ring resonators in silicon photonic circuits have been widely studied and implemented in systems for biosensing [1], telecommunications [2] and generation of photon pairs for quantum optics experiments [3]. The resonator Q-factor, defined by the roundtrip loss and coupling coefficient, is typically a static property of the device realised in the design stage. In this work a method by which to...
This article proposes a high-Q value Whispering-Gallery Mode (WGM) microdisk resonator, which is surrounded by photonic crystal with square lattice. Finite element method (FEM) is performed to model the microdisk resonator, and an ultrahigh quality factor (Q) value of 1.37×108 can be achieved at the wavelength of 1435.4nm. The proposed microdisk resonator is realized on a silicon-on-insulator (SOI)...
Owing to the negative thermo-optic coefficient (TOC) of titanium dioxide, the real effective modal index of Cu-TiO2-Si hybrid plasmonic waveguides can be potentially temperature independent. High-performance Cu-TiO2-Si waveguide-ring resonators (WRRs) are experimentally demonstrated on SOI platform using standard CMOS technology. TOC of the group index is measured to be ~1.09×10-4 K-1 for a WRR with...
We experimentally demonstrate two-stage self-coupled optical waveguide (SCOW) resonators. Coupled-resonator-induced-transparency (CRIT) and high-order filtering features are observed. Resonance spectrum is tunable via a p-i-p thermal resistor or a p-i-n diode.
We discuss the use of active and passive InP membrane structures, heterogeneously integrated onto SOI passive circuits, for switching applications such as gating, wavelength conversion and all-optical flip-flopping. Devices include microdisk lasers and resonators, as well as travelling wave structures, in either electrically pumped or unpumped configuration. We also pay some attention to the fabrication...
This paper describes a simple process method for obtaining submicron capacitive electrode gaps for lateral vibrating square plate resonators and the resulting advantages. A novel electrostatic actuation method is proposed to achieve submicron electrode resonator gaps below the fabrication limitation given by conventional optical lithography. The structures are built of single crystal silicon using...
We demonstrate ultrafast optical control of near field coupled metamaterial resonances. We observed dynamical transition of the metamaterial resonances to change its state from coupled to decoupled, and back to the coupled state under photoexcitation.
Silicon micro tuning forks are used as highly frequency selective sound detector for photoacoustic spectroscopy. The resonant properties and temperature dependencies of these sensors are investigated using the example of a fiber coupled methane sensor.
A compact tunable directional coupler is realized on a silicon photonic platform. The power splitting ratio can be widely tuned through a transverse temperature gradient induced by an asymmetrically placed integrated heater.
We show that optimum designs of optical parametric oscillators require different pump and signal/idler coupling, suggesting novel microphotonic geometries. Normalized models with linear/nonlinear loss show that Si can oscillate at 1550nm below certain free-carrier-to-cavity-photon-lifetime ratios.
We report defect-state-absorption photocurrent in PN-diode-integrated silicon microrings at 1550 nm. We demonstrate a cavity-enhanced responsivity of 3.1 mA/W upon 0 V, and 173 mA/W upon −10 V with a 3dB bandwidth of 10 GHz.
We investigate how thermal stress impacts silica disk resonators by comparing measurements with a finite element and an analytical model. Thicker oxide layers and proper control of undercut enable ultrahigh optical performance and mechanical stability.
We report chip-scale electro-mechanical detection of near-IR optical intensity modulation at 174.2MHz and 1.198GHz in silicon. This constitutes the first experimental demonstration of a photon to phonon translator in a CMOS compatible platform.
Submicron lithium niobate waveguides and resonators are demonstrated on silicon by a novel and reliable ion implantation and wafer bonding technique. Waveguide ridges are formed by selective oxidation of tantalum to avoid etching lithium niobate.
We study methods to improve the Q of a variety of highly-stressed resonators for cavity optomechanics. We realize ultrahigh-Q metal/Si3N4 membranes and crystalline membranes, and have begun to control external dissipation via modified support structures.
We present a silicon microring resonator with a lithium niobate top cladding and integrated tuning electrodes. The silicon ring functions as an optically transparent conductor to yield a DC tunability of 12.5 pm/V.
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