It is well known that this year is the 60th anniversary of the first laser operation by Ted Maiman on 16 May 1960. To celebrate this important event, HPL initiates to organize a feature collection of articles to recognize the 60th anniversary. For this purpose, we invite pioneers in the laser area to contribute review, commentary or research articles on laser development and applications.
The acceleration of polarized electrons, positrons, protons and ions in strong laser and plasma fields is a very attractive option for obtaining polarized beams in the multi-mega-electron volt range. Recently, there has been substantial progress in the understanding of the dominant mechanisms leading to high degrees of polarization, in the numerical modeling of these processes and in their experimental implementation. This review paper presents an overview on the current state of the field, and on the concepts of polarized laser–plasma accelerators and of beam polarimetry.