Integrated photonics is a powerful contender in the race for a fault-tolerant quantum computer, claiming to be a platform capable of scaling to the necessary number of qubits. This necessitates the use of high-quality...
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Integrated photonics is a powerful contender in the race for a fault-tolerant quantum computer, claiming to be a platform capable of scaling to the necessary number of qubits. This necessitates the use of high-quality quantum states, which we create here using an all-around high-performing photon source on an integrated photonics platform. We use a photonic molecule architecture and broadband directional couplers to protect against fabrication tolerances and ensure reliable operation. As a result, we simultaneously measure a spectral purity of 99.1 +/- 0.1%, a pair generation rate of 4.4 +/- 0.1 MHz mW(-2), and an intrinsic source heralding efficiency of 94.0 +/- 2.9%. We also see a maximum coincidence-to-accidental ratio of 1644 +/- 263. We claim over an order of magnitude improvement in the trivariate trade-off among source heralding efficiency, purity, and brightness. Future implementations of the source could achieve in excess of 99% purity and heralding efficiency using the lowest reported propagation losses.
An efficient photorefractive effect triggered by pyroelectricity is demonstrated in slab waveguides constituted of magnesium oxide (MgO)-doped LiNbO3 film on insulator. A microwatt-level continuous wave guided at 532 ...
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An efficient photorefractive effect triggered by pyroelectricity is demonstrated in slab waveguides constituted of magnesium oxide (MgO)-doped LiNbO3 film on insulator. A microwatt-level continuous wave guided at 532 nm is self-trapped to form a 10 mu m FWHM beam triggered by only a few degrees of temperature increase of the sample. A fast self-focusing response time on the order of milliseconds is measured for milliwatts of injected beam, more than two orders of magnitude faster than in the undoped LiNbO3 film. Long lived 2-D induced waveguides are found to be written in the films.
Waveguiding across the visible spectrum in an unmodified bulk CMOS chip is reported. The chip is fabricated in a standard CMOS process, and a simple wet etch removes metal in predetermined locations to expose glass ri...
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Waveguiding across the visible spectrum in an unmodified bulk CMOS chip is reported. The chip is fabricated in a standard CMOS process, and a simple wet etch removes metal in predetermined locations to expose glass rib waveguides. A modified Euler bend is introduced to improve bend radii by nearly an order of magnitude in the rib waveguides, and upper-bound losses are measured at visible wavelengths. These losses range from 6.2 dB/cm at 450 nm to 3.2 dB/cm at 650 nm and represent the lowest losses reported at visible wavelengths in unmodified bulk CMOS.
We present the properties and performance of fluorescentwaveguidelattices as coatings for solar cells, designed to address the significantmismatch between the solar cell's spectral response range andthe solar spec...
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We present the properties and performance of fluorescentwaveguidelattices as coatings for solar cells, designed to address the significantmismatch between the solar cell's spectral response range andthe solar spectrum. Using arrays of microscale visible light opticalbeams transmitted through photoreactive polymer resins comprisingacrylate and silicone monomers and fluorescein o,o '-dimethacrylate comonomer, we photopolymerize well-structuredfilms with single and multiple waveguide lattices. The materials exhibitedbright green-yellow fluorescence emission through down-conversionof blue-UV excitation and light redirection from the dye emissionand waveguide lattice structure. This enables the films to collecta broader spectrum of light, spanning UV-vis-NIR overan exceptionally wide angular range of +/- 70 degrees. When employedas encapsulant coatings on commercial silicon solar cells, the polymerwaveguide lattices exhibited significant enhancements in solar cellcurrent density. Below 400 nm, the primary mode of enhancement isthrough down-conversion and light redirection from the dye emissionand collection by the waveguides. Above 400 nm, the primary modesof enhancement were a combination of down-conversion, wide-angle lightcollection, and light redirection from the dye emission and collectionby the waveguides. Waveguide lattices with higher dye concentrationsproduced more well-defined structures better suited for current generationin encapsulated solar cells. Under standard AM 1.5 G irradiation,we observed nominal average current density increases of 0.7 and 1.87mA/cm(2) for single waveguide lattices and two intersectinglattices, respectively, across the full +/- 70 degrees range and revealoptimal dye concentrations and suitable lattice structures for solarcell performance. Our findings demonstrate the significant potentialof incorporating down-converting fluorescent dyes in polymer waveguidelattices for improving the current spectral and angular response ofsolar cell
Frequency conversion in nonlinear materials is an extremely useful solution to the generation of new optical frequencies. Often, it is the only viable solution to realize light sources highly relevant for applications...
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Frequency conversion in nonlinear materials is an extremely useful solution to the generation of new optical frequencies. Often, it is the only viable solution to realize light sources highly relevant for applications in science and industry. In particular, supercontinuum generation in waveguides, defined as the extreme spectral broadening of an input pulsed laser light, is a powerful technique to bridge distant spectral regions based on single-pass geometry, without requiring additional seed lasers or temporal synchronization. Owing to the influence of dispersion on the nonlinear broadening physics, supercontinuum generation had its breakthrough with the advent of photonic crystal fibers, which permitted an advanced control of light confinement, thereby greatly improving our understanding of the underlying phenomena responsible for supercontinuum generation. More recently, maturing in fabrication of photonic integrated waveguides has resulted in access to supercontinuum generation platforms benefiting from precise lithographic control of dispersion, high yield, compact footprint, and improved power consumption. This Review aims to present a comprehensive overview of supercontinuum generation in chip-based platforms, from underlying physics mechanisms up to the most recent and significant demonstrations. The diversity of integrated material platforms, as well as specific features of waveguides, is opening new opportunities, as will be discussed here.
Micro-Electro-Mechanical Systems (MEMS) entered the frequency and timing control world in the late 90's and since then a rapid spread of novel and high-performance solutions have been experienced to respond to the...
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Micro-Electro-Mechanical Systems (MEMS) entered the frequency and timing control world in the late 90's and since then a rapid spread of novel and high-performance solutions have been experienced to respond to the market requests. In particular, Phononic Crystals (PnC), which are defined as periodic materials with extraordinary properties in terms of guiding, isolation, focusing and steering of elastic and acoustic waves, have been recently proposed as an intriguing ingredient in the design of MEMS circuits. In this work, we propose a novel electro-mechanical circuit able to efficiently couple two High Frequency (HF) MEMS resonators through a defect based PnC MEMS waveguide. In particular, we prove both numerically and experimentally the efficient coupling of an input and an output MHz MEMS capacitive resonator oscillating according to both an in-plane and out-of-plane flexural mode. 2023-0050
To prevent the crosstalk between adjacent waveguides in photonic integrated circuits, the minimum thickness of the cladding layers is around half a wavelength, which imposes a fundamental limitation to further integra...
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To prevent the crosstalk between adjacent waveguides in photonic integrated circuits, the minimum thickness of the cladding layers is around half a wavelength, which imposes a fundamental limitation to further integration and miniaturization of photonic circuits. Here, we reveal that epsilon-near-zero claddings, either isotropic or anisotropic, can break the above bottleneck by prohibiting the crosstalk for the modes with magnetic field polarized in the z direction at a deep-subwavelength thickness (e.g., ? (0)/30, ? (0) is the free-space wavelength), therefore bestowing ultra-compact waveguide systems. The physical origin of this remarkable effect attributes to the divergent impedance of epsilon-near-zero materials far beyond those of dielectric or epsilon-negative claddings. Through full-wave simulations and microwave experiments, we have verified the effectiveness of the ultrathin epsilon-near-zero cladding in crosstalk prohibition. Our finding reveals the significant impact of impedance difference in waveguide designs and opens a promising route toward ultra-compact photonic chips.
Hyperuniform disordered solid (HUDS) structures can provide large, uniform, complete, and isotropic light confinement at the nanoscale after precise design. Based on the HUDS structures, in-plane light confinement for...
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Hyperuniform disordered solid (HUDS) structures can provide large, uniform, complete, and isotropic light confinement at the nanoscale after precise design. Based on the HUDS structures, in-plane light confinement for developing photonic integrated circuits is also explored. To improve the performance of HUDS devices, researchers have mainly focused on cell size or cell distribution optimization in HUDS, which suffers from time-consuming computation or moderate photonic bandgap (PBG) modification. Here, a morphology engineering method is demonstrated to tailor HUDS PBGs and improve HUDS waveguide devices for transverse electric mode. The results show that the Bezier-curve-decorated HUDS devices can achieve a maximum of about 75% PBG width increase, 1.5 dB transmittance improvement in a 10 & mu;m long HUDS waveguide, improved quality factors of HUDS-cladding microring resonators, and device fabrication compatibility with foundry processing. This study opens new avenues for the development of unprecedented devices for exploring light field regulation, nonlinear optics, and sensing.
Rapid advancements in the communications and semiconductor industries have resulted in the trend to move device operations to higher frequencies, with particular interest in the terahertz (THz) band of the electromagn...
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Rapid advancements in the communications and semiconductor industries have resulted in the trend to move device operations to higher frequencies, with particular interest in the terahertz (THz) band of the electromagnetic spectrum. We demonstrate waveguided spintronic THz emitters consisting of a SiNx/Fe/Pt/SiNx film stack on Si/SiO2 and SiO2 substrates. Linearly polarized optical laser pulses are coupled to the devices and their modal characteristics are determined by their polarization angle relative to the waveguide plane. By varying the optical pump polarization angle, we demonstrate modulation of the power of the generated THz radiation by up to 87%. We envision that the small device footprint in conjunction with the simplicity of the fabrication process and compatibility with various semiconductor platforms will enable such structures to be utilized for various on -chip applications where they will work in tandem with photonic and electronic circuitry.
The non-Hermitian models, which are symmetric under parity (P) and time-reversal (T) operators, are the cornerstone for the fabrication of new ultra-sensitive optoelectronic devices. However, providing the gain in suc...
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The non-Hermitian models, which are symmetric under parity (P) and time-reversal (T) operators, are the cornerstone for the fabrication of new ultra-sensitive optoelectronic devices. However, providing the gain in such systems usually demands precise control of nonlinear processes, limiting their application. In this paper, to bypass this obstacle, we introduce a class of time-dependent non-Hermitian Hamiltonians (not necessarily Floquet) that can describe a two-level system with temporally modulated on-site potential and couplings. We show that implementing an appropriate non-Unitary gauge transformation converts the original system to an effective one with a balanced gain and loss. This will allow us to derive the evolution of states analytically. Our proposed class of Hamiltonians can be employed in different platforms such as electronic circuits, acoustics, and photonics to design structures with hidden PT-symmetry potentially without imaginary onsite amplification and absorption mechanism to obtain an exceptional point.(c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
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