Recently, researchers from the Energy and Materials Science Research Center of the University of Tsukuba in Japan, inspired by the "Lotus Effect", successfully developed a tunable laser based on liquid droplets.
It is reported that its core new ionic liquid drop can work like a laser, which is equivalent to a flexible, durable and pneumatically adjustable laser. This is also the world's first liquid laser oscillator known to realize reversible tuning based on gas convection.
Unlike those "liquid drop lasers" that cannot work in the atmosphere in the past, this new scheme enables the laser to be used in daily environment and remain stable for up to a month. Researchers said that this new type of ionic liquid drop would be expected to bring cheaper and more flexible optical communication equipment; It can also be used to realize inkjet printing, and the printing color can change according to the shape of the droplet.
Previously, "droplet lasers" could not be used in general open environment conditions - they would evaporate unless they were enclosed in containers. In the new research, researchers mixed an ionic liquid called 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4) with a dye to make it a laser. The reason for choosing this liquid is that it evaporates very slowly and the surface tension is relatively large.
After mixing, they then coated the quartz substrate with tiny fluorinated silica nanoparticles to achieve the "self-cleaning" effect of repelling liquid on its surface. When EMIBF4 is deposited on it from the pipette, the tiny droplets almost remain spherical. The test results of the research team show that the droplet can remain stable for at least 30 days.
In addition, Professor Hiroshi Yamagishi, the first author of the study, said that the mathematical calculation showed that the ideal shape and optical properties of this ionic liquid droplet can remain unchanged even when exposed to gas convection. They also found that the shape advantage of the droplet itself and its stability in anti-evaporation make the droplet maintain optical resonance when excited by a laser pump source. Nitrogen blowing can achieve laser peak adjustment in the range of 645-662 nm by slightly deforming the droplet shape.
In addition to building optical communication equipment with better performance, this new laser droplet can also be used as a very sensitive humidity sensor or gas flow detector.
The researchers also used a commercial inkjet printing device, which is equipped with a 3D printer head capable of processing viscous liquid. The laser droplet array printed can work without further processing.
The results of this study show that the production and manufacturing of this "droplet laser" is highly scalable and easy to operate, so it can be easily applied to the production of cheap sensors or optical communication equipment and other scenarios. In addition, this research may lead to new airflow detectors or cheaper optical fiber communication equipment.
The above research has received strong support from institutions and platforms such as the Japan Science and Technology Promotion Agency (JST), and the relevant research results have been published recently in the top academic journal of optics - Laser&Photonics Reviews.
Source: OFweek
