Laser-plasma coupling for enhanced ablation of GaAs with combined femtosecond and nanosecond pulses.

The laser-plasma interactions that occur during the ablation of solid materials by a femtosecond filament superimposed with a lower-intensity nanosecond pulse are investigated. Pulses of 50 fs duration with intensities of ∼10 W/cm centered at 800 nm are combined with 8 ns pulses at 1064 nm with ∼10 W/cm intensity with delays of ±40 ns on crystalline GaAs targets in air. For each delay, the volume of material removed by a single femtosecond-nanosecond dual-pulse is compared to the laser-plasma interactions that are captured with ultrafast shadowgraph imaging of the plasma and shockwave generated by each pulse.

The Role of Executive Function and Theory of Mind in Pragmatic Computations.

In sentences such as "Some dogs are mammals," the literal semantic meaning ("Some and possibly all dogs are mammals") conflicts with the pragmatic meaning ("Not all dogs are mammals," known as a scalar implicature). Prior work has shown that adults vary widely in the extent to which they adopt the semantic or pragmatic meaning of such utterances, yet the underlying reason for this variation is unknown. Drawing on theoretical models of scalar implicature derivation, we explore the hypothesis that the cognitive abilities of executive function (EF) and theory of mind (ToM) contribute to this observed variation.

Filament conductivity enhancement through nonlinear beam interaction.

Laser filament applications relying on filament plasma conductivity are limited by their low electron densities and corresponding short lifetimes. Filament plasma formation, an intensity-dependent process, is limited by the clamping of the filament core intensity. Consequently, increasing initial beam energy results in the breakup of the beam into multiple filaments rather than the enhancement of the electron density and conductivity of an individual filament.

Pragmatics and social meaning: Understanding under-informativeness in native and non-native speakers.

Foreign-accented non-native speakers sometimes face negative biases compared to native speakers. Here we report an advantage in how comprehenders process the speech of non-native compared to native speakers. In a series of four experiments, we find that under-informative sentences are interpreted differently when attributed to non-native compared to native speakers.

Direct wavefront measurements of filaments in the assisted-collapse regime.

Wavefront measurements are used to characterize the process of filament formation in air under assisted-collapse conditions. Direct wavefront evolution within the filament, measured for the first time, is used to characterize the role of energy reservoir in filament formation. This information provides new insights into the filament process and phase sensitive applications such as engineered plasma waveguides.