Bubble laser

Laser made of a bubble

An ordinary bubble can serve as an optofluidic laser. These bubble lasers have been made of dye-doped soap solutions and smectic liquid crystal. In a bubble laser, the bubble itself serves as the optical resonator. Uniquely, bubble lasers exhibit hundreds of regularly spaced resonant frequencies called whispering gallery modes, named for the Whispering Gallery in St. Paul's Cathedral in London. Researchers have found that the emission spectrum of a bubble laser is highly dependent on the bubble's environment; changing ambient air pressure or electric fields changes the size of the bubble, and therefore the wavelengths of laser emission.

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