The realization of an all-optical transistor, in which one "gate" photon controls a "source" light beam, is a long-standing goal in optics. By stopping a light pulse in an atomic ensemble contained ...inside an optical resonator, we realized a device in which one stored gate photon controls the resonator transmission of subsequently applied source photons. A weak gate pulse induces bimodal transmission distribution, corresponding to zero and one gate photons. One stored gate photon produces fivefold source attenuation and can be retrieved from the atomic ensemble after switching more than one source photon. Without retrieval, one stored gate photon can switch several hundred source photons. With improved storage and retrieval efficiency, our work may enable various new applications, including photonic quantum gates and deterministic multiphoton entanglement.
Ultrabroad-bandwidth radiofrequency pulses offer significant applications potential, such as increased data transmission rate and multipath tolerance in wireless communications. Such ...ultrabroad-bandwidth pulses are inherently difficult to generate with chip-based electronics due to limits in digital-to-analog converter technology and high timing jitter. Photonic means of radiofrequency waveform generation, for example, by spectral shaping and frequency-time mapping, can overcome the bandwidth limit in electronic generation. However, previous bulk optic systems for radiofrequency arbitrary waveform generation do not offer the integration advantage of electronics. Here, we report a chip-scale, fully programmable spectral shaper consisting of cascaded multiple-channel microring resonators, on a silicon photonics platform that is compatible with electronic integrated circuit technology. Using such a spectral shaper, we demonstrate the generation of burst radiofrequency waveforms with programmable time-dependent amplitude, frequency and phase profiles, for frequencies up to 60 GHz. Our demonstration suggests potential for chip-scale photonic generation of ultrabroad-bandwidth arbitrary radiofrequency waveforms.
Eutectic gallium–indium (EGaIn), a liquid metal with a melting point close to or below room temperature, has attracted extensive attention in recent years due to its excellent properties such as ...fluidity, high conductivity, thermal conductivity, stretchability, self‐healing capability, biocompatibility, and recyclability. These features of EGaIn can be adjusted by changing the experimental condition, and various composite materials with extended properties can be further obtained by mixing EGaIn with other materials. In this review, not only the are unique properties of EGaIn introduced, but also the working principles for the EGaIn‐based devices are illustrated and the developments of EGaIn‐related techniques are summarized. The applications of EGaIn in various fields, such as flexible electronics (sensors, antennas, electronic circuits), molecular electronics (molecular memory, opto‐electronic switches, or reconfigurable junctions), energy catalysis (heat management, motors, generators, batteries), biomedical science (drug delivery, tumor therapy, bioimaging and neural interfaces) are reviewed. Finally, a critical discussion of the main challenges for the development of EGaIn‐based techniques are discussed, and the potential applications in new fields are prospected.
This review article gives a comprehensive overview of the unique properties and wide applications of liquid metal eutectic gallium–indium (EGaIn). The working principles for the EGaIn‐based devices are illustrated and the developments of EGaIn‐related techniques are summarized. The main challenges for the development of EGaIn‐related techniques are analyzed and the potential applications of EGaIn in the new fields are prospected.
Starting from Tesla's principles of wireless power transfer a century ago, this critical review outlines recent magneto-inductive research activities on wireless power transfer with the transmission ...distance greater than the transmitter coil dimension. It summarizes the operating principles of a range of wireless power research into 1) the maximum power transfer and 2) the maximum energy efficiency principles. The differences and the implications of these two approaches are explained in terms of their energy efficiency and transmission distance capabilities. The differences between the system energy efficiency and the transmission efficiency are also highlighted. The review covers the two-coil systems, the four-coil systems, the systems with relay resonators and the wireless domino-resonator systems. Related issues including human exposure issues and reduction of winding resistance are also addressed. The review suggests that the use of the maximum energy efficiency principle in the two-coil systems is suitable for short-range rather than mid-range applications, the use of the maximum power transfer principle in the four-coil systems is good for maximizing the transmission distance, but is under a restricted system energy efficiency (<;50%); the use of the maximum energy efficiency principle in relay or domino systems may offer a good compromise for good system energy efficiency and transmission distance on the condition that relay resonators can be placed between the power source and the load.
This open access book presents theoretical framework and sample applications of variant construction. The first part includes the components variant logic, variant measurements, and variant maps, ...while the second part covers sample applications such as variation with functions, variant stream ciphers, quantum interference, classical/quantum random sequences, whole DNA sequences, and multiple-valued pulse sequences. Addressing topics ranging from logic and measuring foundation to typical applications and including various illustrated maps, it is a valuable guide for theoretical researchers in discrete mathematics; computing-, quantum- and communication scientists; big data engineers; as well as graduate and upper undergraduate students.
The demand for lightweight converters with high control performance and low acoustic noise led to an increase in switching frequencies of hard switched two-level low-voltage 3-phase converters over ...the last years. For high switching frequencies, converter efficiency suffers and can be kept high only by employing cost intensive switch technology such as SiC diodes or CoolMOS switches; therefore, conventional IGBT technology still prevails. In this paper, the alternative of using three-level converters for low-voltage applications is addressed. The performance and the competitiveness of the three-level T-type converter (3LT 2 C) is analyzed in detail and underlined with a hardware prototype. The 3LT 2 C basically combines the positive aspects of the two-level converter such as low conduction losses, small part count and a simple operation principle with the advantages of the three-level converter such as low switching losses and superior output voltage quality. It is, therefore, considered to be a real alternative to two-level converters for certain low-voltage applications.
A fully-integrated, silicon photonic transceiver is demonstrated in a silicon-on-insulator process using photonic microring resonator modulators for low power consumption. The trade-offs between ...bandwidth and extinction ratio are discussed and motivate the use of transmit pre-emphasis for ring modulators to increase the interconnect data rate. The transmitter and receiver is demonstrated to data rates of 25 Gb/s with a BER of 10 ^-12. The total power consumption of the transceiver is 256 mW and demonstrates a link efficiency of 10.2 pJ/bit excluding laser power. At 25 Gb/s, the driver operates at 7.2 pJ/bit.
This paper investigates the capacitor-current-feedback active damping for the digitally controlled LCL-type grid-connected inverter. It turns out that proportional feedback of the capacitor current ...is equivalent to virtual impedance connected in parallel with the filter capacitor due to the computation and pulse width modulation (PWM) delays. The LCL-filter resonance frequency is changed by this virtual impedance. If the actual resonance frequency is higher than one-sixth of the sampling frequency (f s /6), where the virtual impedance contains a negative resistor component, a pair of open-loop unstable poles will be generated. As a result, the LCL-type grid-connected inverter becomes much easier to be unstable if the resonance frequency is moved closer to f s /6 due to the variation of grid impedance. To address this issue, this paper proposes a capacitor-current-feedback active damping with reduced computation delay, which is achieved by shifting the capacitor current sampling instant towards the PWM reference update instant. With this method, the virtual impedance exhibits more like a resistor in a wider frequency range, and the open-loop unstable poles are removed; thus, high robustness against the grid-impedance variation is acquired. Experimental results from a 6-kW prototype confirm the theoretical expectations.
We present an experimental realization of an autonomous Maxwell's demon, which extracts microscopic information from a system and reduces its entropy by applying feedback. It is based on two ...capacitively coupled single-electron devices, both integrated on the same electronic circuit. This setup allows a detailed analysis of the thermodynamics of both the demon and the system as well as their mutual information exchange. The operation of the demon is directly observed as a temperature drop in the system. We also observe a simultaneous temperature rise in the demon arising from the thermodynamic cost of generating the mutual information.
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