Improved phase purity in 2D hybrid perovskite thin films with horizontal crystal orientation was achieved through slow crystallization employing lead-complexing solvent additives.

Hydrodynamic optically-field-ionized (HOFI) plasma channels up to 100 mm long are investigated. Optical guiding is demonstrated of laser pulses with a peak input intensity of 6 × 10 17 W cm −2 through 100 mm long plasma channels with on-axis densities measured interferometrically to be as low as n e0 ¼ ð1.0 AE 0.3Þ × 10 17 cm −3. Guiding is also observed at lower axial densities, which are inferred from magneto-hydrodynamic simulations to be approximately 7 × 10 16 cm −3. Measurements of the power attenuation lengths of the channels are shown to be in good agreement with those calculated from the measured transverse electron density profiles. To our knowledge, the plasma channels investigated in this work are the longest, and have the lowest on-axis density, of any free-standing waveguide demonstrated to guide laser pulses with intensities above >10 17 W cm −2 .

A new formula is derived which gives electron mobility values in argon in good agreement with experiment and calculation. The effect of mercury on electron mobility in argon is expressed as a correction factor. The theoretical expression obtained is applied to discharge conditions for which exact results are known, and the results are compared. The values of mu e obtained have been used to calculate axial electron density, showing good agreement with experiment.

We demonstrate through experiments and numerical simulations that low-density, low-loss, meter-scale plasma channels can be generated by employing a conditioning laser pulse to ionize the neutral gas collar surrounding a hydrodynamic optical-field-ionized (HOFI) plasma channel. We use particle-in-cell simulations to show that the leading edge of the conditioning pulse ionizes the neutral gas collar to generate a deep, low-loss plasma channel which guides the bulk of the conditioning pulse itself as well as any subsequently injected pulses. In proof-of-principle experiments, we generate conditioned HOFI (CHOFI) waveguides with axial electron densities of n e0 ≈ 1×10 17 cm −3 and a matched spot size of 26 μm. The power attenuation length of these CHOFI channels was calculated to be L att = (21 ± 3) m, more than two orders of magnitude longer than achieved by HOFI channels. Hydrodynamic and particle-in-cell simulations demonstrate that meter-scale CHOFI waveguides with attenuation lengths exceeding 1 m could be generated with a total laser pulse energy of only 1.2 J per meter of channel. The properties of CHOFI channels are ideally suited to many applications in high-intensity light-matter interactions, including multi-GeV plasma accelerator stages operating at high pulse repetition rates.