Conference Agenda

We demonstrate the generation of short optical pulses in a pair of phase-coupled photonic crystal nanolasers exploiting non-Hermitian coupling. Two waveguide-coupled nanocavities are operated below their individual lasing thresholds and subjected to asymmetric optical pumping, such that a transient carrier-induced detuning modifies the interference conditions between them. This dynamically controls the gain and loss of the collective modes, and, upon crossing a resonance condition, leads to the rapid release of stored carrier energy as an optical pulse. A rate-equation model captures the interplay between carrier dynamics and modal coupling and reproduces the observed behavior. These results indicate that non-Hermitian coupling can be used to control the effective cavity losses in time, providing a route to pulse generation in integrated photonic systems.

Here, we present chains of plasmonic nanoparticles that support flat bands. We combine these nanoparticle chains with emitters and optically pump this system. We experimentally demonstrate lasing in the flat band mode. We extend the chains to two-dimensional chain lattices and study how real- and momentum-space emission depend on array geometry, pump polarization, and pump intensity.

We demonstrate the fabrication of electrically pumped random laser diodes by post-processing Fabry-Perot laser facets using focused ion beam milling. By introducing a random mask of milled slots, we engineer disordered optical feedback. The modified devices exhibit unstable multimode emission, characterized by abrupt spectral transitions. Experimental results reveal significant power and spectral hysteresis, attributed to strong modal competition within the complex cavity. These results highlight FIB milling as a precise tool for tailoring random laser dynamics, offering potential for non-linear signal processing and advanced imaging applications.

Noise is a key ingredient in nonlinear dynamics, giving rise to diverse and complex behaviours. Although significant control over collective multimode states of light has been demonstrated in driven nonlinear optical systems, the role of noise introduced through the drive remains largely unexplored. Here, we show that noise can induce localisation transitions in a collective liquid-like state of light. By injecting controlled temporal noise into the modulation of a fast-gain laser cavity, a randomly varying linear potential is created along the synthetic frequency lattice consitituted by its modes. As the noise amplitude increases, three regimes of lattice occupation emerge: an extended state, a Gaussian distribution, and ultimately exponential localisation. Time-resolved spectroscopy of individual noise realisations reveals qualitatively different dynamics: transport persists in the Gaussian regime under the influence of the fluctuating potential, whereas it is fully suppressed at all times in the localised regime.

We demonstrate a TM mode novel circulator design where magneto-optically coupled waveguides under a transverse magnetic field enable unidirectional transmission and circulation. The reflectionless, lossless device achieves >30 dB isolation across an 80 nm bandwidth.