题目内容
Atoms fall back from a high energy level to a low energy. When they fall back, they release energy. This energy is emitted in the form of （ ）, and light is produced.
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The first laser was developed by Mayman of the United States in （ ）.
In 1958, Towns and Arthur Show Low proposed the "Laser Principle" through experiments and won the ( )of 1964.
The four characteristics of laser light refer to ( ).
( ) can be used for low-power irradiation or repair of skin, facial features, maternity, etc., because it has the effects of stimulation, anti-inflammatory, analgesia and vasodilation.
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