Researchers created a tunable laser based on liquid droplets that can be inkjet-printed and have a color that changes depending on the shape, potentially leading to cheaper and more flexible optical communication devices. They demonstrated a straightforward method for creating ionic liquid microdroplets that function as flexible, long-lasting, and pneumatically tunable lasers. Unlike existing “droplet lasers,” which cannot operate in the presence of air, the developers believe this new development could lead to lasers that can be used in everyday situations.
The researchers used an artificial “lotus effect” to create liquid droplets that can act like lasers and stay stable for up to a month. In this study, an ionic liquid known as 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4) was combined with a dye that allowed it to function as a laser. This liquid was selected because it evaporates slowly and has high surface tension.
The surface of a quartz substrate is then coated with tiny fluorinated silica nanoparticles to repel liquids. When EMIBF4 is applied with a pipette, the tiny droplets remain nearly completely spherical. The researchers demonstrated that the droplet could be stable for at least 30 days. Mathematical calculations predicted that the droplet’s desired morphological and optical properties would persist even when exposed to gas convection.
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