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High-precision biosensors for single or few molecules detection play a central role in numerous key fields, such as environmental monitoring and healthcare for early-stage disease diagnosis. In the last decade, laser biosensors have been investigated as proofs of concept, and several technologies have been proposed. Here we propose a demonstration of polymeric whispering gallery microlasers as biosensors for detecting proteins at low concentrations. Free space microlasers have the great advantage of working without any need for waveguiding for input excitation or output signal detection. The photonic microsensors can be easily patterned on microscope slides and operate in air and solution. We could detect down to 400 pg of protein without specific binding, and few tens of pg/mL with specific binding. [ABSTRACT FROM AUTHOR]

Deformed microdisc cavities possess versatile application potential ranging from microlasers to sensors. Here, we investigate arrays of several coupled microcavity resonators. The coupling interaction between the cavities induces a wide range of features that sensitively depend on, and therefore can be controlled via, the intercavity distance. We use semiclassical methods from mesoscopic optics to characterise the system and its dynamics in real and phase space using Husimi functions. Our findings can inspire novel optical devices such as supersensors or novel light sources. [ABSTRACT FROM AUTHOR]

Ray-wave correspondence has proven a powerful tool in mesoscopic optics, in particular in the description of deformed microdisc cavities with a versatile application potential ranging from microlasers to sensors. New material classes such as graphene-based systems have enriched the field by adding Dirac Fermion optics as well as anisotropic material properties as further system parameters. The trigonally warped dispersion relation in bilayer-graphene billiards generalizes the concept of birefringence and opens unconventional ways of trajectory control in the interplay of dispersion relation and the cavity geometry as we illustrate in this contribution. [ABSTRACT FROM AUTHOR]

Bio-integrated lasers, that are lasers made of biological and biocompatible materials and implanted into cells and tissues, are gaining interest from the research community. Here we show how whispering gallery mode microlasers and microcavities made of solid beads or droplets can be used for sensing different processes in biological materials including inside cells. By making microcavities of a predefined size they can also be used to encode some information and for cell tracking. Sensing and tracking can be applied to highly scattering tissues. [ABSTRACT FROM AUTHOR]

This work describes the different steps of the design of a cylindric Optical Parametric Oscillator. It is based on a BBO nonlinear crystal shaped as a partial cylinder to be pumped by a commercial micro-laser at 0.355 μm for an energetic and sub-nanosecond emission continuously tunable between 0.4 μm and 0.9 μm. [ABSTRACT FROM AUTHOR]

Bistability and ultrafast wavelength switching in coupled-cavity microlasers is investigated from the point of view of application in optical memory. Theoretical guidelines for optimizing the switching performance are drawn. A tradeoff between switching time and energy is found. Both these properties can be controlled by a proper choice of switching pulse parameters. At optimum, switching times of less than 10 ps with switching energy around 15–30 fJ are predicted. The results are confirmed in direct numerical simulations for a 2D photonic crystal microlaser. [ABSTRACT FROM AUTHOR]