A team of scientists have demonstrated tunable red, green and blue single-mode microlasers in an optimized heterogeneously coupled cavities constructed with three spherical microcavities incorporated with distinct gain media. The microcavities with perfect circle boundary and smooth surface were applied as high-quality WGM resonators.
Benefiting from the outstanding flexibilities, RGB lasing was obtained by doping the corresponding dyes into different WGM microcavities. Different color-emissive spherical cavities were integrated to form a heterogeneously coupled system by using a strategy of nanoarchitectonics. In such a heterogeneously coupled system, each individual microsphere serves as not only the laser source but also the filter for the other resonator, which would enable the output of single-mode laser from individual microcavities.
Furthermore, they fabricated heterogeneously coupled system, which permits optical coupling between multiple resonators, thereby realizing tunable RGB single-mode microlasers. The results demonstrate a unique approach for the modulation of lasing modes in heterogeneously coupled cavities and shed new light on the generation of microlasers capable of emitting over the full visible spectrum with high spectral purity for optoelectronic integrated system.