The color is achieved by using specific laser diodes that emit light with a wavelength between approximately 380 to 420 nanometers. Unlike red and green lasers, which are based on more mature laser technologies, purple lasers are a product of advancements in semiconductor laser. Washington D. InGaN) and emitting around 400–480 nm, have been developed quite successfully, now offering substantially better output powers and device lifetimes than green diode lasers. Researchers at Toshiba Materials and Devices Laboratories (Kawasaki, Japan) have developed an indium gallium nitride-based blue-purple-emitting (417 nm) diode laser that emits a pulsed beam at room temperature; they are reportedly working "around the clock" to achieve continuous wave (CW). Electrical pumping can be via a DC current (as in laser diodes), an electrical discharge (noble gas lasers and excimer lasers), or a radio-frequency discharge (most CO 2 lasers).
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