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Electrical tunability of saturable absorption is demonstrated in a graphene/SOI hybrid waveguide. The saturation modulation depth is tunable between 0 and 2.2 dB (∼0–40% decrease of absorption at saturation), with saturation powers between ∼1.25–2.5 W.
We demonstrate broadband frequency comb generation in the mid-infrared from 2.3 to 3.5 μm in a Si3N4 microresonator with Q=850,000 fabricated using an optimized process for decreasing intrinsic losses and overcoming stress limitations.
We fabricate a vertically stacked photodetector device containing silicon nanowire photodetectors formed above a silicon substrate that also contains a photodetector. The substrate photodetector converts light not absorbed by the nanowires to photocurrent.
The history of the laser industry has shown that for a particular laser type to be widely adopted for materials processing depends on the availability of a minimum laser power at a realistic cost. The development of supra 100 watt thulium fiber lasers means that another laser type has now been added to that relatively short list. Initially developed for a surgical application, this laser has unique...
The unwanted photoacoustic pressure force in photoexpansion spectroscopy, which comes from light absorption of the sample not below the AFM tip, was suppressed at the heterodyne frequency of laser pulses and piezo-driven cantilever oscillation.
We demonstrate an octave spanning, 1.9–6.2 μm supercontinuum generation in a low loss silicon on a sapphire (SOS) nanowire. This establishes SOS as a promising new platform for integrated nonlinear photonics in the mid-IR.
We introduce a mechanism for nonlinear optical power transmission using partially absorptive resonances in photonic crystal slabs. We experimentally demonstrate increasing, decreasing, and nonmonotonic transmission as a function of optical power.
The ability to transfer electrons from valence to conduction band states in a semiconductor is the basis of modern electronics. Here, attosecond spectroscopy is used to resolve this process in real-time. The excitation of electrons across the band-gap of silicon by few-cycle laser pulses is found to induce lasting modifications of the XUV absorbance spectrum in steps synchronized with the laser electric...
Free-standing thin-film flexible Si1−xGex saturable absorber with Si/Ge composition-ratio dependent saturable absorbance is demonstrated to passively mode-lock the erbium-doped fiber laser for delivering a pulsewidth of 330 fs at a modulation depth of 16%.
Due to its unique crystal structure, black phosphorus (BP) shows anisotropic electric and optical properties. In this work, we demonstrate its optical anisotropy by measuring its different absorptions of TE and TM modes travelling in silicon photonic waveguides. In the experiment, when BP crystal armchair axis is aligned perpendicularly to waveguide, the measured absorption coefficients for TE and...
This paper utilizes the method of adding a mass source and a damping term into the fluid governing equation for generating and absorbing the second order stokes wave. A nonlinear mathematic model for a raft-type wave energy converter with three floaters is proposed based on the Lagrange formulation. A number of simulations are accomplished in CFD software by numerically solving the non-linear mathematical...
We report near-infrared and high-speed silicon photo-detectors capable of sub-bandgap light absorption based on the optically-assisted tunneling induced by a large electric field.
We investigate the strong modulation instability at telecommunication band in a silicon-organic hybrid slot waveguide. The pulse train is obtained via pump pulses with pulse width of 10 ps and peak power of 250 mW.
We utilize near- and mid-IR ultrafast laser radiation to investigate the processing of crystalline silicon with different dopants. A numerical model is adopted to simulate the material response depending on the wavelength and the dopant concentration.
The photo-thermo electrical conversion system using black silicon and gold nanoparticles have been suggested for energy harvesting. Efficient light absorption with black silicon and plasmonic photo-thermal energy conversion was successfully improving the energy conversion efficiency of light. Totally ∼50% of improvements has been achieved with optimization of Au nanoparticles diameters and density.
We theoretically investigated the modulation speed of Si photonic crystal slow light modulators. Optimizing the doping profile of p/n junction reduces the RC time constant and enhances the speed to 40 Gbps.
Electroabsorption modulators based on the epsilon-near-zero (ENZ) effect of ITO are theoretically investigated. They are designed to work in the mid-infrared. We demonstrate that the modulator length is made smaller than 1.16 μm.
Molecular alignment behavior of pentacene molecules sublimed on photoreactive liquid-crystalline polymer (PLCP) layer that are work as a photoalignment layer were explored. Pentacene molecule aligned perpendicular to the director of PLCP with edge-on to the substrate while pentacene on surface region of the bilayer forms the same structure as pentacene-alone substrate that covered the anisotropic...
Germanium-on-silicon is a promising platform for planar photonics over the entire mid-infrared range. We report here grating coupled Ge-on-Si waveguides with record low losses of 0.6dB/cm, multimode interferometers and Mach-Zehnder interferometers.
We report waveguide-integrated Ge electro-absorption modulators operating at 1615nm wavelength with 3dB bandwidth beyond 50GHz and a capacitance of 10fF. A 2V voltage swing enables 4.6dB DC extinction ratio for 4.1dB insertion loss.
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