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We demonstrate the three-fold post-chirped-pulse-amplification (post-CPA) pulse compression of a high peak power laser pulse using allyl diglycol carbonate (CR39), which was selected as the optimal material for near-field self-phase modulation out of a set of various nonlinear plastic materials, each characterized with respect to its nonlinear refractive index and optical transmission. The investigated materials could be applied for further pulse compression at high peak powers, as well as for gain narrowing compensation within millijoule-class amplifiers. The post-CPA pulse compression technique was tested directly after the first CPA stage within the POLARIS laser system, with the compact setup containing a single 1 mm thick plastic sample and a chirped mirror pair, which enabled a substantial shortening of the compressed pulse duration and, hence, a significant increase in the laser peak power without any additional modifications to the existing CPA chain.

We present pulse stretching with an intracavity Offner-type pulse stretcher applied to a high-energy, short-pulse laser system. The compact intracavity design, offering a tunable stretching factor, allows the pulses to be stretched to several nanoseconds and, at the same time, to be amplified to 100 μJ. The stretched pulses have been further amplified with the high-power laser system Polaris and have been recompressed to durations as short as 102 fs, reaching peak powers of 100 TW. Furthermore, the temporal intensity contrast is investigated and compared to the formerly used stretcher setup.

We report on results from the fully diode-pumped chirped-pulse amplification laser system Polaris. Pulses were amplified to a maximum energy of 54.2 J before compression. These pulses have a full width at half-maximum spectral bandwidth of 18 nm centered at 1033 nm and are generated at a repetition rate of 0.02 Hz. To the best of our knowledge, these are the most energetic broadband laser pulses generated by a diode-pumped laser system so far. Due to the limited size of our vacuum compressor, only attenuated pulses could be compressed to a duration of 98 fs containing an energy of 16.7 J, which leads to a peak power of 170 TW. These pulses could be focused to a peak intensity of 1.3×10 21   W/cm 2 . Having an ultra-high temporal contrast of 10 12 with respect to amplified spontaneous emission these laser pulses are well suited for high-intensity laser-matter experiments.

We present tunable spectral filters (TSFs) as a variable and precisely adjustable method to control the spectral gain of short-pulse laser systems. The TSFs provide a small residual spectral phase and a high damage threshold, and generate no pre- or post-pulses. The method is demonstrated for two different laser materials and can be applied as an intracavity compensation in regenerative amplifiers as well as a method for pre-compensation in high-energy multipass amplifiers. With this method, a full width at half-maximum bandwidth of 23.9 nm could be demonstrated in a diode-pumped, 50 J Yb:CaF 2 amplifier.

We demonstrate the generation of 86 fs, 35 mJ, high-contrast laser pulses at 1030 nm with a repetition rate of 1 Hz from a diode-pumped double chirped-pulse amplification setup. The pulses exhibit a spectral bandwidth exceeding 27 nm full width at half-maximum. This could be achieved by using a laser architecture comprising two stages of chirped pulse amplification with a cross-polarized wave generation filter in between, by applying spectral shaping and by increasing the spectral hard-clip of the second stretcher. These are, to the best of our knowledge, the shortest pulses at the mJ level with ultra-high contrast generated with a diode-pumped front end at 1030 nm.

We report the amplification of laser pulses at a center wavelength of 1034 nm to an energy of 16.6 J from a fully diode-pumped amplifier using Yb:CaF2 as the active medium. Pumped by a total optical power of 300 kW from high-power laser diodes, a gain factor of g=6.1 was achieved in a nine-pass amplifier configuration agreeing with numerical simulations. A measured spectral bandwidth of 10 nm full width at half-maximum promises a bandwidth-limited compression of the pulses down to a duration of 150 fs. These are, to our knowledge, the most energetic laser pulses achieved from a diode-pumped chirped-pulse amplifier so far.

We report on the first generation of high-contrast, 164 fs duration pulses from the laser system POLARIS reaching focused peak intensities in excess of 2×10(20) W/cm2. To our knowledge, this is the highest peak intensity reported so far that has been achieved with a diode-pumped, solid-state laser. Several passive contrast enhancement techniques have been specially developed and implemented, achieving a relative prepulse intensity smaller than 10(-8) at t=-30 ps before the main pulse. Furthermore a closed-loop adaptive-optics system has been installed. Together with angular chirp compensation, this method has led to a significant reduction of the focal spot size and an increase of the peak intensity.

We describe a method that can be used for the coherent addition of laser pulses. As different laser pulses are initially generated in a laser-pulse compressor equipped with a tiled grating, such a coherent addition is indispensable in order to maximize the intensity in the laser far field. We present measurements in this context where, up to now, an unavoidable difference in the grating constants between the phased gratings reduced the maximum achievable intensity. The method significantly facilitates the high-precision alignment of a tiled grating compressor and could also be used for a coherent addition of laser pulses.

We present what we believe to be the first terawatt diode-pumped laser employing single-crystalline Yb:CaF(2) as the amplifying medium. A maximum pulse energy of 420 mJ at a repetition rate of 1 Hz was achieved by seeding with a stretched femtosecond pulse 2 ns in duration, preamplified to 40 mJ. After recompression, a pulse energy of 197 mJ and a duration of 192 fs were obtained, corresponding to a peak power of 1 TW. Furthermore, nanosecond pulses containing an energy of up to 905 mJ were generated without optical damage.