Spectral phase effects and control requirements of coherent beam combining for ultrashort ultrahigh intensity laser systems

Abstract

Based on the premise that further improvements to the size and damage threshold of large-aperture optical components are severely limited, coherent beam combining (CBC) is a promising way to scale up the available peak power of pulses for ultrashort ultrahigh intensity laser systems. Spectral phase effects are important issues and have a significant impact on the performance of CBC. In this work, we analyze systematically factors such as spectral dispersions and longitudinal chromatism, and get the general spectral phase control requirements of CBC for ultrashort ultrahigh intensity laser systems. It is demonstrated that different orders of dispersion influence intensity shape of the combined beam, and high-order dispersions affect the temporal contrast of the combined beam, while the number of the channels to be combined has little impact on the temporal Strehl ratio (SR) of the combined beam. In addition, longitudinal chromatism should be controlled effectively since it has a detrimental effect on the combined beam at the focal plane, both temporally and spatially.

In-house beam-splitting pulse compressor for high-energy petawatt lasers

“…3). The sharing of the first pair of gratings also make the two compressed pulses easy to tune and achieve similar spectral phase, which is important for the tiled-aperture combining method [20][21]26]. This is because people do not need to consider the dispersion difference induced by the first pair of gratings.…”

“…As a result, in comparison to that of outside beamsplitting design shown in Figure 1(b), the novel in-house beam splitting design would be easier to obtain the same spectral phase for the two splitting beams. Then, it will help to achieve an efficiency tiled-aperture combining which is affected by the spectral phase differences of independent beams [20,26].…”

“…At last, the compressed four laser beams can be combined by using the tiled-aperture combining method [19][20][21][22][23][24][25][26]. In the case, the piston phase, pointing stability, wavefront, and GDD dispersion should be carefully controlled.…”

Characterization of ultrashort double pulses and their application in attosecond physics

“…In Eqn. 2.14, all derivatives, also known as dispersion coefficients, have different effects on the propagating pulse [3], [16], [17]. These are the following:…”