Quantum interference in time

Since the very beginning of quantum physics, a hundred years ago, it has been known that all particles in the universe fall into two categories: fermions and bosons. For instance, the protons found in atomic nuclei are fermions, ...

New light amplifier can boost the potential of photonics

A new light amplifier developed at the University of Twente not only boosts the light signals on a photonic chip, but it also enhances the applicability of those chips. Thanks to stronger light signals, detector chips for ...

Start of most sensitive search yet for dark matter axion

Thanks to low-noise superconducting quantum amplifiers invented at the University of California, Berkeley, physicists are now embarking on the most sensitive search yet for axions, one of today's top candidates for dark matter.

Research raises hope for erbium-based integrated photonics device

An Arizona State University researcher has made another breakthrough using the rare-earth metal erbium as the gain material for an optical amplifier, this time with an achievement that will enable its use for the first time ...

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Generally, an amplifier or simply amp, is a device for increasing the power of a signal.

In popular use, the term usually describes an electronic amplifier, in which the input "signal" is usually a voltage or a current. In audio applications, amplifiers drive the loudspeakers used in PA systems to make the human voice louder or play recorded music. Amplifiers may be classified according to the input (source) they are designed to amplify (such as a guitar amplifier, to perform with an electric guitar), the device they are intended to drive (such as a headphone amplifier), the frequency range of the signals (Audio, IF, RF, and VHF amplifiers, for example), whether they invert the signal (inverting amplifiers and non-inverting amplifiers), or the type of device used in the amplification (valve or tube amplifiers, FET amplifiers, etc.).

A related device that emphasizes conversion of signals of one type to another (for example, a light signal in photons to a DC signal in amperes) is a transducer, a transformer, or a sensor. However, none of these amplify power.

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