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Blue light means big progress for perovskite-based LEDs

Researchers at Linköping University, Sweden, have developed efficient blue light-emitting diodes based on halide perovskites. "We are very excited about this breakthrough," says Feng Gao, professor at Linköping University. ...

Study confirms dark coating can reduce satellite reflectivity

Observations conducted by the Murikabushi Telescope of Ishigakijima Astronomical Observatory confirmed that dark coating can reduce satellite reflectivity by half. There are concerns that numerous artificial satellites in ...

Novel quantum dots facilitate coupling to quantum memory systems

Researchers at the University of Basel and Ruhr-Universität Bochum have realized quantum dots—tiny semiconductor nanostructures—that emit light close to the red part of the spectrum with ultra-low background noise. Quantum ...

Invisible organic light-emitting diodes reach new world record

You can't see it with the naked eye, but a new fluorescent organic light-emitting diode (OLED) could shed light on the development of innovative applications in devices such as smartphone and television displays using near-infrared ...

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Wavelength

In physics, the wavelength of a sinusoidal wave is the spatial period of the wave – the distance over which the wave's shape repeats. It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves. Wavelength is commonly designated by the Greek letter lambda (λ). The concept can also be applied to periodic waves of non-sinusoidal shape. The term wavelength is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids.

Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths.

Examples of wave-like phenomena are sound waves, light, and water waves. A sound wave is a periodic variation in air pressure, while in light and other electromagnetic radiation the strength of the electric and the magnetic field vary. Water waves are periodic variations in the height of a body of water. In a crystal lattice vibration, atomic positions vary periodically in both lattice position and time.

Wavelength is a measure of the distance between repetitions of a shape feature such as peaks, valleys, or zero-crossings, not a measure of how far any given particle moves. For example, in waves over deep water a particle in the water moves in a circle of the same diameter as the wave height, unrelated to wavelength.

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