To: 19/02/2020 14:00
Why is it difficult to make small, sub-wavelength in size, lasers? Nowadays we have access to powerful lasers, built to serve many purposes, but what if we wanted to have miniaturized versions of them? To do so we would need to consider materials and techniques other than the traditional; even so, as we start reducing the size of the laser, eventually we will have to encounter a trade-off between the system dimensions and the quality of the laser.
Recently, our group proposed a design that overcomes this apparent dead end [1-3]. The concept is based on using dark resonant states in low-loss dielectrics as an equivalent of the laser cavity, that is, a dark state essentially replaces the mirrors used in big lasers. This is possible because dark states are localized, resonant electromagnetic modes that do not radiate. Therefore they are used to separate the gain-coupled resonant photonic state responsible for macroscopic stimulated emission from the coupling to free-space propagating modes, allowing independent adjustment of the lasing state and its coherent radiation output.
In this talk, I will give a detailed discussion of the key-functionalities and benefits of this design, such as radiation tunability, directionality, sub-wavelength integration, and simple layer-by-layer fabrication.
 Droulias, S., Jain, A., Koschny, T. & Soukoulis, C. M. Novel lasers based on resonant dark states. Phys. Rev. Lett. 118, 073901 (2017).
 Droulias, S., Jain, A., Koschny, T. & Soukoulis, C. M. Fundamentals of metasurface lasers based on resonant dark states. Phys. Rev. B 96, 155143 (2017).
 Droulias, S., Koschny, T. & Soukoulis, C. M. Finite-Size effects in metasurface lasers based on resonant dark states. ACS Photonics 5(9), 3788 (2018).