Injectable laser resonators require Photonic capsules

The research group of KAIST presented photonic tablets, using microfluidic technology for the injectable laser. The diameter of the tablets is comparable to a stable gas and liquid media. This is why it can be injectable in any target volume. 

Professor Shin-Hyun Kim, research group head in the Department of Chemical and Biomolecular Engineering, has applied a significant nature’s optical property. Professor Kim, who has researched deeply on these photonic materials and inspired by qualities things such as Morpho butterfly. 

Chrysina gloriosa, generally known as the glorious beetle, a green color beetle same as leaves when illuminated by left-handed, circularly-polarized light when showing no color with right-handed, circularly-polarized light. This significant optical ensure to help the beetles to protect them from predators and help them to communicate with each other. 

The principle behind this interesting optical property of the beetles relies on helical nanostructures with left-handedness that is present on the shell of the beetles. The helical structures reflect a circularly-polarized light with the same handedness of the helix at the wavelength selected by the helical pitch through optical interference.

This nanostructure would create artificially by using liquid crystals. A helical arrangement with LCs is referred to as cholesteric LCs (CLCs). The CLCs is dependent on the reflection of light in an exact manner as the beetles and used for different photonic applications. In a specified case CLCs have been introduced to format a mirrorless resonators laser, which is a conventional laser system. In fact, the CLCs, which are as film type large, can show unidirectional emission. This restricts the use of CLC microenvironment resonators. 

Professor Kim and his group have encapsulated the CLC s with double shells by using microfluidic technology to get rid of these limitations. The inside tank is a layer of water, which promotes the LC molecules alignment and the outer shell is a polymer layer of plastic, which secures the stability of the capsule and enables deformation of mechanical reversible. This capsule allows for the laser emissions of omnidirectional. In fact, the intensity of the laser and its direction could further control by the pills deforming, during the tunable remains in wavelength. The new kind of CLC laser resonator is determining for laser in different biomedical applications. 

Professor Kim said that The nanostructure helical used in the laser resonator resembles and this is the Christina gloriosa shell. Humans learn engineer materials and nature. They create something unprecedented.