The field of high-power lasers is at a critical stage of making major breakthroughs and developing applications, especially for high-peak power, ultra-intense, ultrashort lasers and high-energy continuous lasers with high average power. Over the past five years, ultra-intense, ultra-short laser facilities based on chirped pulse amplification and their derivative technologies have broken through 10 petawatts (PW) of peak power, and spectral beams combining continuous-wave laser equipment with hundreds of kilowatts of average power have been delivered. Reflective holographic surface-relief diffraction gratings are the core components of current high-power lasers. The Shanghai Institute of Optics and Fine Mechanics (SIOM) develops the meter-scale (1620 mm×1070 mm) pulse compression grating (PCG) and the advanced spectral beam combining grating (SBCG) worldwide. In the next five years, global development works for the delivery of 100 PW lasers will be online. In addition, the output power of high-energy continuous lasers will also enter a new stage. Accordingly, the high-power laser will necessitate the development of billion dollar industries. Advanced diffraction gratings will play an important supportive role in contributing to the power growth of high-power lasers. Currently, both domestically and abroad, the field of high-power laser diffraction grating exists in both a growth period and a stable period. Therefore, it is necessary to review and look forward to the research trends in the field of high-power laser diffraction gratings from the perspective of those who have experienced the development of the field in China and are oriented to the real needs and real problems.

This paper is dedicated to the 60th anniversary of SIOM and takes this opportunity to salute all those who have participated in and contributed to high-power laser grating in China.

In this study, the domestic and international research progress of PCG and SBCG over the past 40 years has been reviewed based on the demand (Fig. 2) for reflective holographic gratings by the two major technologies of chirped pulse amplification and spectral beam combining, which are represented by ultra-intense, ultrashort laser and high-power fiber laser systems (Fig. 1). Section II of this paper briefly describes the classification and preparation of reflective surface relief gratings (Figs. 3 and 4). Section III highlights the research progress of metal pulse compression gratings in spectral bandwidth expansion, large aperture fabrication (Fig. 7), and laser-induced damage threshold (LIDT) enhancement. Section IV focuses on the line density increase (Fig. 20) and thermal loading performance enhancement (Figs. 21‒23) of multilayer dielectric polarization-independent SBCGs.

The development and construction of high-power lasers are in full swing. This paper reviews the progress of domestic and international research on pulsed compressed gold gratings and all-dielectric merging gratings over the past 40 years.

Currently, pulse compression gold gratings are mainly developed around the center wavelengths of 800 and 910 nm to achieve a spectral bandwidth of 100 or 200 nm. The concept of fewer cycles or even single-cycle pulse compression has recently been established, and the implementation of the bandwidth demand has risen to 400 nm. Hence, the development of advanced ultra-broadband meter-scale gratings needs to be accelerated to capture the scientific and technological high ground in China. In addition, in the construction goal of 100 kW and even megawatt lasers, the development of advanced SBCGs will continue to be laid out along the two main tasks of high line density and high heat-load performance improvement in the future. Simultaneously, although the problem of laser-induced damage to optical components has coexisted with the development of high-power lasers, LIDT data and studies of gratings are still insufficient, nearly half a century later. The complexity and multidisciplinary nature of grating damage will inject fresh vitality into the field of grating research in the future as the parametric diversity of high-power lasers increases.

Although China ventured into the development of high-power gratings later than did foreign countries, it has made huge progress over the past decade and is now among the elite ranks of high-power-grating nations. SIOM, as a representative of China, developed the largest meter-scale (1620 mm×1070 mm) PCG and advanced SBCG worldwide. Over the next few years, China's high-power laser grating development needs to overcome the large aperture, high LIDT, high diffraction efficiency, broadband, and other key challenges, which are strongly supported by scientific research management institutions and the cooperation of all relevant units.