The Experts below are selected from a list of 32535 Experts worldwide ranked by ideXlab platform
Yann Le Coq - One of the best experts on this subject based on the ideXlab platform.
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Spectral purity transfer between optical wavelengths at the $10^{-18}$ level
Nature Photonics, 2014Co-Authors: Daniele Nicolodi, Rodolphe Le Targat, Bérengère Argence, Wei Zhang, Giorgio Santarelli, Yann Le CoqAbstract:Ultra-stable lasers and optical frequency combs have been the enabling technologies for the tremendous progress of precise optical spectroscopy in the last ten years. To improve laser frequency stabilization beyond the thermal-noise fundamental limit of traditional room-temperature high-finesse optical cavities, new solutions have been recently developed. These being complex and often wavelength specific, the capability to transfer their spectral purity to any optical wavelengths is highly desirable. Here we present an optical frequency comb based scheme transferring a $4.5 \times 10^{-16}$ fractional frequency Stability from a 1062 nm wavelength laser to a 1542 nm laser. We demonstrate that this scheme does not hinder the transfer down to $3 \times 10^{-18}$ at one second, two orders of magnitude below previously reported work with comparable systems. This exceeds by more than one order of magnitude the Stability of any optical oscillator demonstrated to date, and satisfies the Stability Requirement for quantum-projection-noise limited optical lattice clocks.
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Spectral purity transfer between optical wavelengths at the 10^−18 level
Nature Photonics, 2014Co-Authors: Daniele Nicolodi, Rodolphe Le Targat, Bérengère Argence, Wei Zhang, Giorgio Santarelli, Yann Le CoqAbstract:Ultrastable lasers and optical frequency combs have been the enabling technologies for the tremendous progress made in precise optical spectroscopy over the last ten years^ 1 , 2 . Recently, to improve the laser frequency stabilization beyond the thermal noise fundamental limit of traditional room-temperature high-finesse optical cavities^ 3 , new solutions have been developed^ 4 , 5 , 6 , 7 . These are complex and often wavelength-specific, so the capability to transfer their spectral purity to any optical wavelength is therefore highly desirable. Here, we present an optical frequency comb-based scheme that transfers 4.5 × 10^−16 fractional frequency Stability from a 1,062 nm wavelength laser to a 1,542 nm laser. We demonstrate that this scheme does not hinder the transfer down to 4 × 10^−18 at 1 s, one order of magnitude below previously reported work with comparable systems^ 8 , 9 , 10 , 11 , 12 , 13 . This exceeds, by more than one order of magnitude, the Stability of any optical oscillator demonstrated to date^ 6 , and satisfies the Stability Requirement for quantum projection noise-limited optical lattice clocks^ 14 . An optical-frequency comb-based scheme is demonstrated that transfers a 4.5 × 10^−16 fractional frequency Stability from a 1,062-nm-wavelength laser to a 1,542-nm-wavelength laser. Transfer is also reported down to 4 × 10^−18 at 1 s, which is one order of magnitude below that of previously reported work with comparable systems.
Daniele Nicolodi - One of the best experts on this subject based on the ideXlab platform.
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Spectral purity transfer between optical wavelengths at the $10^{-18}$ level
Nature Photonics, 2014Co-Authors: Daniele Nicolodi, Rodolphe Le Targat, Bérengère Argence, Wei Zhang, Giorgio Santarelli, Yann Le CoqAbstract:Ultra-stable lasers and optical frequency combs have been the enabling technologies for the tremendous progress of precise optical spectroscopy in the last ten years. To improve laser frequency stabilization beyond the thermal-noise fundamental limit of traditional room-temperature high-finesse optical cavities, new solutions have been recently developed. These being complex and often wavelength specific, the capability to transfer their spectral purity to any optical wavelengths is highly desirable. Here we present an optical frequency comb based scheme transferring a $4.5 \times 10^{-16}$ fractional frequency Stability from a 1062 nm wavelength laser to a 1542 nm laser. We demonstrate that this scheme does not hinder the transfer down to $3 \times 10^{-18}$ at one second, two orders of magnitude below previously reported work with comparable systems. This exceeds by more than one order of magnitude the Stability of any optical oscillator demonstrated to date, and satisfies the Stability Requirement for quantum-projection-noise limited optical lattice clocks.
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Spectral purity transfer between optical wavelengths at the 10^−18 level
Nature Photonics, 2014Co-Authors: Daniele Nicolodi, Rodolphe Le Targat, Bérengère Argence, Wei Zhang, Giorgio Santarelli, Yann Le CoqAbstract:Ultrastable lasers and optical frequency combs have been the enabling technologies for the tremendous progress made in precise optical spectroscopy over the last ten years^ 1 , 2 . Recently, to improve the laser frequency stabilization beyond the thermal noise fundamental limit of traditional room-temperature high-finesse optical cavities^ 3 , new solutions have been developed^ 4 , 5 , 6 , 7 . These are complex and often wavelength-specific, so the capability to transfer their spectral purity to any optical wavelength is therefore highly desirable. Here, we present an optical frequency comb-based scheme that transfers 4.5 × 10^−16 fractional frequency Stability from a 1,062 nm wavelength laser to a 1,542 nm laser. We demonstrate that this scheme does not hinder the transfer down to 4 × 10^−18 at 1 s, one order of magnitude below previously reported work with comparable systems^ 8 , 9 , 10 , 11 , 12 , 13 . This exceeds, by more than one order of magnitude, the Stability of any optical oscillator demonstrated to date^ 6 , and satisfies the Stability Requirement for quantum projection noise-limited optical lattice clocks^ 14 . An optical-frequency comb-based scheme is demonstrated that transfers a 4.5 × 10^−16 fractional frequency Stability from a 1,062-nm-wavelength laser to a 1,542-nm-wavelength laser. Transfer is also reported down to 4 × 10^−18 at 1 s, which is one order of magnitude below that of previously reported work with comparable systems.
Xuehua Wang - One of the best experts on this subject based on the ideXlab platform.
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Improve the robustness of digitally-controlled LCL-filtered inverters against grid impedance variation with a lag compensator
2017 IEEE Energy Conversion Congress and Exposition (ECCE), 2017Co-Authors: Xuehua Wang, Xinbo RuanAbstract:Capacitor-current-feedback active damping method is commonly used in LCL-filtered grid-connected inverters, which attenuates the resonance peak by emulating a virtual resistor in parallel with the filter capacitor. Taking the digital control delay into account, the emulation component becomes frequency-dependent, and it will turn negative when the filter resonance frequency becomes higher than one-sixth of the sampling frequency, resulting in the inconsistent Stability Requirement. Due to the variation of grid impedance, the filter resonance frequency will vary in a wide range, and the inconsistent Stability Requirement may occur, which will pose a challenge to the inverter Stability. In this paper, the Stability of digitally controlled LCL-filtered inverter is studied first, and a phase lag compensator is introduced to ensure the Stability Requirement keeps consistent even if the filter resonance frequency reaches the Nyquist frequency. Thus the Stability-robustness of the inverter to the grid impedance variation is improved. Finally, the validation of the proposed compensation method is verified by simulation and experimental results.
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Full feedforward of grid voltage for grid-connected inverter with LCL filter to suppress current distortion due to grid voltage harmonics
IEEE Transactions on Power Electronics, 2010Co-Authors: Xuehua Wang, Shangwei Liu, Xinbo Ruan, Chi K. TseAbstract:The grid-connected inverter with an LCL filter has the ability of attenuating the high-frequency current harmonics. However, the current distortion caused by harmonics in the grid voltage is difficult to be eliminated. Increasing the loop gain can reduce the current distortion, but this approach is compromised by the system Stability Requirement. Without increasing the loop gain, applying feedforward of the grid voltage can suppress the effect of grid voltage harmonics. This paper proposes the feedforward function of the grid voltage for the grid-connected inverter with an LCL filter. Specifically, the proposed feedforward function involves proportional, derivative, and second derivative of the grid voltage, and can be simplified according to the dominant harmonics in the grid voltage. The proposed feedforward scheme can effectively suppress the current distortion arising from the grid voltage harmonics, and the steady-state error of the injected current can be substantially reduced even if a conventional proportional and integral regulator is applied. A 6-kW experimental prototype has been tested to verify the effectiveness of the proposed feedforward scheme.
Giorgio Santarelli - One of the best experts on this subject based on the ideXlab platform.
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Spectral purity transfer between optical wavelengths at the $10^{-18}$ level
Nature Photonics, 2014Co-Authors: Daniele Nicolodi, Rodolphe Le Targat, Bérengère Argence, Wei Zhang, Giorgio Santarelli, Yann Le CoqAbstract:Ultra-stable lasers and optical frequency combs have been the enabling technologies for the tremendous progress of precise optical spectroscopy in the last ten years. To improve laser frequency stabilization beyond the thermal-noise fundamental limit of traditional room-temperature high-finesse optical cavities, new solutions have been recently developed. These being complex and often wavelength specific, the capability to transfer their spectral purity to any optical wavelengths is highly desirable. Here we present an optical frequency comb based scheme transferring a $4.5 \times 10^{-16}$ fractional frequency Stability from a 1062 nm wavelength laser to a 1542 nm laser. We demonstrate that this scheme does not hinder the transfer down to $3 \times 10^{-18}$ at one second, two orders of magnitude below previously reported work with comparable systems. This exceeds by more than one order of magnitude the Stability of any optical oscillator demonstrated to date, and satisfies the Stability Requirement for quantum-projection-noise limited optical lattice clocks.
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Spectral purity transfer between optical wavelengths at the 10^−18 level
Nature Photonics, 2014Co-Authors: Daniele Nicolodi, Rodolphe Le Targat, Bérengère Argence, Wei Zhang, Giorgio Santarelli, Yann Le CoqAbstract:Ultrastable lasers and optical frequency combs have been the enabling technologies for the tremendous progress made in precise optical spectroscopy over the last ten years^ 1 , 2 . Recently, to improve the laser frequency stabilization beyond the thermal noise fundamental limit of traditional room-temperature high-finesse optical cavities^ 3 , new solutions have been developed^ 4 , 5 , 6 , 7 . These are complex and often wavelength-specific, so the capability to transfer their spectral purity to any optical wavelength is therefore highly desirable. Here, we present an optical frequency comb-based scheme that transfers 4.5 × 10^−16 fractional frequency Stability from a 1,062 nm wavelength laser to a 1,542 nm laser. We demonstrate that this scheme does not hinder the transfer down to 4 × 10^−18 at 1 s, one order of magnitude below previously reported work with comparable systems^ 8 , 9 , 10 , 11 , 12 , 13 . This exceeds, by more than one order of magnitude, the Stability of any optical oscillator demonstrated to date^ 6 , and satisfies the Stability Requirement for quantum projection noise-limited optical lattice clocks^ 14 . An optical-frequency comb-based scheme is demonstrated that transfers a 4.5 × 10^−16 fractional frequency Stability from a 1,062-nm-wavelength laser to a 1,542-nm-wavelength laser. Transfer is also reported down to 4 × 10^−18 at 1 s, which is one order of magnitude below that of previously reported work with comparable systems.
Rodolphe Le Targat - One of the best experts on this subject based on the ideXlab platform.
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Spectral purity transfer between optical wavelengths at the $10^{-18}$ level
Nature Photonics, 2014Co-Authors: Daniele Nicolodi, Rodolphe Le Targat, Bérengère Argence, Wei Zhang, Giorgio Santarelli, Yann Le CoqAbstract:Ultra-stable lasers and optical frequency combs have been the enabling technologies for the tremendous progress of precise optical spectroscopy in the last ten years. To improve laser frequency stabilization beyond the thermal-noise fundamental limit of traditional room-temperature high-finesse optical cavities, new solutions have been recently developed. These being complex and often wavelength specific, the capability to transfer their spectral purity to any optical wavelengths is highly desirable. Here we present an optical frequency comb based scheme transferring a $4.5 \times 10^{-16}$ fractional frequency Stability from a 1062 nm wavelength laser to a 1542 nm laser. We demonstrate that this scheme does not hinder the transfer down to $3 \times 10^{-18}$ at one second, two orders of magnitude below previously reported work with comparable systems. This exceeds by more than one order of magnitude the Stability of any optical oscillator demonstrated to date, and satisfies the Stability Requirement for quantum-projection-noise limited optical lattice clocks.
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Spectral purity transfer between optical wavelengths at the 10^−18 level
Nature Photonics, 2014Co-Authors: Daniele Nicolodi, Rodolphe Le Targat, Bérengère Argence, Wei Zhang, Giorgio Santarelli, Yann Le CoqAbstract:Ultrastable lasers and optical frequency combs have been the enabling technologies for the tremendous progress made in precise optical spectroscopy over the last ten years^ 1 , 2 . Recently, to improve the laser frequency stabilization beyond the thermal noise fundamental limit of traditional room-temperature high-finesse optical cavities^ 3 , new solutions have been developed^ 4 , 5 , 6 , 7 . These are complex and often wavelength-specific, so the capability to transfer their spectral purity to any optical wavelength is therefore highly desirable. Here, we present an optical frequency comb-based scheme that transfers 4.5 × 10^−16 fractional frequency Stability from a 1,062 nm wavelength laser to a 1,542 nm laser. We demonstrate that this scheme does not hinder the transfer down to 4 × 10^−18 at 1 s, one order of magnitude below previously reported work with comparable systems^ 8 , 9 , 10 , 11 , 12 , 13 . This exceeds, by more than one order of magnitude, the Stability of any optical oscillator demonstrated to date^ 6 , and satisfies the Stability Requirement for quantum projection noise-limited optical lattice clocks^ 14 . An optical-frequency comb-based scheme is demonstrated that transfers a 4.5 × 10^−16 fractional frequency Stability from a 1,062-nm-wavelength laser to a 1,542-nm-wavelength laser. Transfer is also reported down to 4 × 10^−18 at 1 s, which is one order of magnitude below that of previously reported work with comparable systems.
