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The direct generation of mid-infrared optical frequency combs in the region 2.5–4.0 μm from a 1.55-μm conventional and compact erbium-fibre-based femtosecond laser is demonstrated via coherent dispersive wave generation in silicon nitride nanophotonic waveguides.
Biodegradable cellulose-based photonic and plasmonic architectures are fabricated via soft nanoimprinting lithography, and are used for structural colour generation, photoluminescence enhancement and as disposable surface-enhanced Raman scattering substrates.
By sending few-microjoule single-cycle terahertz pulses to a segmented terahertz electron accelerator and manipulator, 70 MV m–1 peak acceleration fields, 2 kT m–1 focusing gradients, 140 µrad fs–1 streaking gradient and bunch compression to 100 fs are achieved.
The Fermi–Pasta–Ulam recurrence process—the recovery of the initial state of a nonlinear system after a certain time—is observed for the first time in a low-loss optical fibre by building a multi-channel, vector optical-time-domain reflectometer.
Optical trapping of metal nanoparticles with conventional ‘tweezers’ can be challenging due to absorption and heating. Now, an opto-thermoelectric trapping approach that exploits heating has been demonstrated.
Observing ultrafast transient dynamics in optics is a challenging task. Two teams in Europe have now independently developed ‘optical oscilloscopes’ that can capture both amplitude and phase information of ultrafast optical signals. Their schemes yield new insights into the nonlinear physics that takes place inside optical fibres.
A highly nonlinear optical response can be used to time-resolve light-induced phase transitions with few-femtosecond to sub-femtosecond accuracy, paving the way for time-resolving highly correlated many-body dynamics in strongly correlated systems with few-femtosecond accuracy.
Heating due to optical losses in metal nanoparticles, which is usually an unwanted side effect, is harnessed to realize low-power opto-thermoelectric nanotweezers.
The use of a time-gated reflection matrix of a scattering medium, in particular via using singular value decomposition and injecting light into the largest time-gated eigenchannel, can lead to a more than tenfold enhancement in light energy delivery in comparison with ordinary wave diffusion cases.
