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Thermal noise is now limiting the most stable lasers that are employed in optical clocks and for precision measurements to a few times 10–17. Laser systems and ways towards further improvements will be presented.
We report on two ultrastable lasers stabilized to single-crystal silicon Fabry-Pérot cavities at 124 K. The lasers show unprecedented thermal noise-limited frequency instabilities of 4×10−17 and linewidths below 10 mHz.
Substrate-transferred crystalline coatings are a groundbreaking new concept for the fabrication of ultralow-loss mirrors. The low defect density single-crystal nature of these semiconductor supermirrors enables the lowest mechanical losses and hence unmatched Brownian noise performance [1], which currently limits the stability of precision optical interferometers. Another outstanding feature of these...
We investigate a novel Ti Chemical Vapor Deposition (CVD Ti) technique for source/drain and trench contact silicidation. This work is a first demonstration of a highly selective, superconformal Ti process that exhibits a low p-type CVD Ti/SiGe:B contact resistivity (pc) down to 2.1×10−9 Ω.cm2 (a 40% reduction vs. PVD Ti), matching the lowest published values [1-5]. A competitive n-type CVD Ti/Si:P...
We outline recent advances in high-performance substrate-transferred crystalline coatings with key results being the demonstration of sub-ppm absorption in the near infrared, as well as preliminary loss measurements in the mid-IR from 3–4 μm.
The tremendous progress with optical atomic clocks asks for super-stable lasers to interrogate the best clock transitions with only a few mHz line width. Previously, we developed a cryogenic silicon Fabry-Perot resonator that demonstrated short-term instability below 1 χ 10−16. We have set up two independent updated systems with the goal of reaching a thermal-noise limited fractional frequency instability...
This paper provides an algorithm for selecting the site and size of dispersed energy storage (DES), in power transmission networks. Firstly, flexibility requirements for each branch are identified through an assessment of the transmission network. From the previous analysis, an evolutionary particle swarm optimization algorithm is applied to find the preferred solution, in terms of DES site and size...
Cavity-Enhanced Direct Frequency Comb Spectroscopy has been applied to buffer gas cooled acetylene achieving a Doppler-limited spectral resolution of 90 MHz. Additionally Time Resolved Frequency Comb Spectroscopy allows for the detection of trans-DOCO in photolysis reaction kinetics with a molecular sensitivity of 1010 cm−3.
A photonic scheme to realize multiple microwave frequencies measurement using SBS is proposed. By coarsely/precisely determine the frequency band/frequency, two frequencies measurement with improved precision of < 1MHz is experimentally achieved.
Unexpected yield loss in high-volume DRAM manufacturing occurs very often as an excursion in critical levels such as high aspect ratio container (HARC) etch in capacitor formation in the device. The main failure mode is polymer formation and plasma density change during the chamber preventive maintenance. In this paper we study the effect of polymer formation on HARC profile at various electrostatic...
Mild cognitive impairment (MCI) is an intermediate stage between normal aging and Alzheimer's disease (AD), and around 10–15% of people with MCI develop AD each year. More recently, MCI has been further subdivided into early and late stages, and there is interest in identifying sensitive brain imaging biomarkers that help to differentiate stages of MCI. Here, we focused on anatomical brain networks...
A photonic scheme to generate microwave signals with hybrid pulse-position modulation and binary phase shift keying format is proposed and experimentally demonstrated. Hybrid PPM-BPSK signals with 0.1ns symbol period and 20GHz carrier frequency are obtained.
In this paper an overview is drawn on energy storage technologies and their application on power systems, from the transmission system operators (TSOs) perspective. Potential constraints to energy storage commissioning are identified and possible solutions described. A set of guidelines for planning energy storage in transmission networks is provided, including a survey on regulatory framework. A...
The reduction of detectors in PET systems, without significantly compromising the PET utility, is an important cost consideration in a PET-system design. Recent advances in algorithm development can be used for enabling the design and assessment of innovative PET systems. In this work, we investigate PET configurations with reduced number of detectors by using the ASD-POCS algorithm that was developed...
A photonic scheme to act as microwave digital synthesizer based on a tunable polarization diversified comb filter and the process of frequency-to-time-mapping is proposed and experimentally demonstrated. 2-ASK/PSK/FSK signals are generated with tunabilities in the bit-rate, duty-cycle and carrier frequencies.
A photonic-assisted microwave phase shifter using phase modulator and fiber-Bragg-grating in a round trip configuration is proposed. The phase of 20∼30 GHz microwave signals can be shifted by properly adjusting the voltage of PM-driving signal.
A novel approach to generate tunable microwave photonic pulse shaping based on modified incoherent frequency-to-time mapping (FTTM) is proposed. By adjusting the product of the bit-rate and the pulsewidth (i.e. BΔT) to introduce the intersymbol interference, we demonstrate the effectiveness of our approach by generating typical UWB and triangular pulses.
Multiform spectral shaping schemes to provide tunability on the shape, free spectral range and bandwidth of microwave photonic signals are reviewed. By utilizing specific dispersion-based conversion techniques, the proposed scheme scan be widely used to achieve flexible manipulation of microwave signals.
This paper focuses on a basic research of out-of-phase synchronization currents of a single phase transformer and its impact on a system of synchronous machine, transformer, switch and grid. The effect of transformer saturation is studied for different switching conditions using the finite element software FLUX 3D. The position of the switch has a significant influence on the peak current. The studied...
We describe recent experimental progress with the JILA Sr optical frequency standard, which has a systematic uncertainty at the 10−16 fractional frequency level, currently limited by frequency shifts due to atomic interactions and room temperature blackbody radiation (BBR). We will discuss systematic measurements of collisional shifts and provide a complete theory to understand these interaction effects...
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