Fig. 1. (a) Scheme of the compressed probe setup and (b) labeled image of the post-compressor station.

Fig. 2. Main and probe pulses before the experiment. (a)–(c) Power amplifier (PA) mode, -shot average for the main and probe pulses, where the error bars are standard deviations of shot-to-shot variations. (a) Red is the main pulse spectrum, while magenta is the main pulse spectral phase. (b) Blue is the probe pulse spectrum, while cyan is probe pulse spectral phase. (c) Red and blue are the main and probe pulse shapes, while cyan is the shortest probe pulse. (d) Down-collimated probe beam spatial profile measured before the fused silica plates by using a low-power infrared laser diode alignment beam.

Fig. 3. On-shot main and probe pulse measurements during one experimental day in several laser modes. The box-and-whisker plots of the main pulse (a) and probe pulse (b) FWHM durations versus the laser mode and main pulse energy. The colored bars represent the 25%–75% ranges, the error bars are the 1.5 interquartile ranges, the horizontal lines are the medians and the squares, dots and circles are the means, outliers and minima, respectively. The dots on the right from the boxes-and-whiskers are the individual shots forming the corresponding histograms. (c) Main (stars) and probe (rings) pulses on the [FWHM, effective pulse width] plane; each point is an individual shot. Color encodes the laser mode.

Fig. 4. Stability of the probe pulse compression and the shortest measured pulses. (a) FWHM histograms for the BA1×2 mode, which provides the optimum average compression. (b) Shortest main and probe pulses; the latter was obtained in the BA2×1 laser shot with the main pulse energy of 4 J and probe pulse energy of approximately 5.8 mJ.

Fig. 5. Analysis of the dependence of probe pulse duration on the probe and main pulse energy. (a) Relative energy fluctuation (standard deviation divided by mean) in 1” apertures near the edge of the main beam (approximately probe location, red) and at the center of the main beam (black) in different laser modes. (b) Probe pulse duration dependence on the estimated probe energy in the PA×6 laser mode. The red line is a one-parameter fit corresponding to Equation (11b) of Ref. [33]. (c) Probe pulse duration dependence on the estimated probe energy for all studied laser modes (solid circles) and estimated^[33,34] probe duration assuming ideal compression (open circles); the right-hand axis shows the motion blur.

Fig. 6. (a)–(d) Representative examples of images produced by the original and down-collimated compressed probe; magnification 10.2, frame size 1920 × 600 pixels, pixel size 1.1 mm × 0.34 mm. The scale bar shown in (d) is common for (a)–(d). (a) Original probe, shadow mode. (b) Down-collimated compressed probe, shadow mode. (c) Down-collimated compressed probe, Schlieren mode. (d) Down-collimated compressed probe, Schlieren mode at an early probe delay. (e) A representative example of fine fringes observed by the compressed probe; note the difference in scale compared to (a)–(d).

Fig. 7. Comparison with other works. Our average BA1×2 data and best BA2×1 data are shown with the red and blue stars, respectively. The figure with other data is reprinted with permission from Ref. [21].