Conference Agenda

We study the spatiotemporal dynamics of asymmetric microcavity semiconductor lasers as function of the resonator geometry. Our experimental and numerical studies elucidate how the classical ray dynamics, dictated by the cavity geometry, affects nonlinear light-matter interaction, which in turn determines lasing dynamics. Our approach to engineering laser dynamics is robust, compact, and has the potential to be applied to controlling other nonlinear complex systems.

We demonstrate a novel and straightforward approach to enhance the nonlinear responses of metamaterials by incorporating them into multipass cells, allowing the pump beam to interact with the metasurface multiple times. As a proof of principle, we achieved phase matching of the second-harmonic generation (SHG) signal with a superlinear dependence on the number of passes. Experimentally, we observed a remarkable tenfold enhancement in the SHG signal from a plasmonic metasurface after nine passes.This approach is generic and compatible with various existing enhancement techniques and metamaterials, offering a versatile method to improve the performance of nonlinear devices.

Recently, superradiant bursts of light have been experimentally observed for a cascaded quantum system. This was realized using an ensemble of waveguide-coupled two-level atoms that exhibit propagation direction-dependent coupling to the waveguide mode. Here, we experimentally study the collective radiative decay of a fully inverted atomic ensemble and measure the second-order correlation function, g^(2)(t1,t2), of the light emitted by the atoms into the waveguide. We observe a g^(2)(0,0) of about 2 at the beginning of the decay, followed by a decrease to g^(2)(t,t) to 1 (where t>0) within the characteristic time scale of the burst dynamics. This built-up of second-order coherence can be interpreted by assuming that, following an initially independent emission, the atoms synchronize during their decay. Interestingly, for ensembles below and above full inversion, g^(2)(t,t)=1 for all times. In addition to these observations, we find an anti-correlation of photon detection events, i.e., g^(2)(t1,t2)<1, in certain parameter regions in which t1 unequal to t2, indicating a temporal sub-structure of the light emerging the ensemble. Our findings can be well described with a model based on the truncated Wigner approximation. Our results contribute to understanding the fundamentals of light-matter interaction and help engineering protocols for the generation of non-classical light.

The Advanced Laser Light Source (ALLS) laboratory provides high-repetition-rate ultrashort light pulses using ytterbium laser technology. Recently, we have developed a novel end-station called time- and angle-resolved photoemission (TR-ARPES) to explore the rapid electron dynamics in quantum materials when subjected to intense optical excitation in the near- and mid-infrared range. These intense pulses are generated using our in-house-built optical parametric amplifier (OPA) ranging from 1.6 to 8 μm with a duration of around 100 fs

Recent years have witnessed remarkable progress in enhancing the supercontinuum (SC) generation in highly nonlinear photonic integrated waveguides. In this study, we conduct a comprehensive investigation into supercontinuum (SC) generation in high-index doped silica glass integrated waveguides. We explore a variety of femtosecond pumping wavelengths and input polarization states, demonstrating coherent octave-spanning SC bandwidth from visible to mid-infrared wavelengths.