Ultrafast and ultra-intense lasers refer to special light fields that have both ultrafast time domain characteristics and ultra-high peak power
characteristics. They have created unprecedented extreme physical conditions such as ultrafast time, ultra-high intensity field, ultra-high
temperature and ultra-high pressure in the laboratory for humans, greatly promoting the development and progress of frontier sciences such
as physics, chemistry, biology, materials, medicine and interdisciplinary disciplines. It can be considered that ultrafast and ultra-intense lasers
are one of the most important tools for frontier basic scientific research to expand human cognition, and in some aspects they are even unique
and irreplaceable research methods.
While promoting the continuous expansion of frontier basic scientific research, ultrafast and ultra-intense laser technology is also facing the
need for new capabilities to support the frontier basic scientific research due to its own deepening exploration, which has given strong traction
to the development of the laser technology system.
(I) Ultrafast lasers and their scientific applications
The future development needs in this direction can be subdivided into attosecond lasers and even zeptosecond lasers, and ultraviolet-
terahertz full-band multi-dimensional parameter-precisely controllable femtosecond ultrafast lasers.
Attosecond lasers and even zettasecond lasers pursue the use of ultrafast lasers with shorter pulse widths to study faster ultrafast processes
inside matter. It is necessary to develop high-performance attosecond (10–18 s) lasers with higher pulse energy, shorter pulse width, and
higher photon energy. The photon energy of attosecond pulses is pushed to the hard X-ray band and gamma-ray band, and the pulse width is
pushed to the zettasecond (10–21 s) time scale, thereby pushing the material level that humans can explore from the atomic/molecular level to
the atomic nuclear scale.
The femtosecond time scale corresponds to ultrafast processes in rich material systems such as atoms/molecules, materials, biological
proteins, and chemical reactions, and has extensive and important applications. With the further expansion and deepening of research, it is
necessary to explore more abundant and complex ultrafast dynamic processes in order to control these ultrafast processes. In order to
modulate and utilize the parametric characteristics of ultrafast lasers in more dimensions, it is necessary not only to expand the spectrum of
femtosecond lasers to the infrared-terahertz band and the vacuum ultraviolet-extreme ultraviolet band, but also to develop precision-controlled
femtosecond ultrafast lasers including multi-dimensional parameters such as time domain, amplitude, phase, spectrum, polarization, and
spatial mode, represented by femtosecond ultrafast lasers with precisely controllable multi-dimensional parameters in the entire band of
extreme ultraviolet-terahertz.
(II) Ultra-intense lasers and their scientific applications
According to the differences in positioning and application targets, this direction can be divided into low repetition rate ultra-high peak power
ultra-intense lasers and high repetition rate high average power ultra-intense lasers. Among them, low repetition rate refers to the laser pulse
repetition frequency of 10 Hz or less, and high repetition rate refers to the laser pulse repetition frequency of 1 kHz or more.
Only by using ultra-intense lasers can humans produce extreme physical conditions in the laboratory that exist only inside cosmic stars and
atomic nuclei. Using low repetition rate ultra-high peak power ultra-intense lasers, we can study frontier physics problems at the microscopic
scale, such as laser particle acceleration, photonuclear physics, and gamma-light-light collisions in the laboratory. We can also study
astrophysical phenomena such as supernova explosions, solar flares, and black hole accretion disk jets at the macroscopic scale. We can also
study gravitational waves, dark matter, vacuum physics, and other frontier basic sciences that expand the unknown of mankind. In response to
the needs of major national theoretical and experimental research, such as laser particle accelerators, nuclear physics such as nuclear
transmutation, high-energy physics, new ways of laser fusion energy, and laser nuclear medicine, low repetition rate ultra-high peak power
ultra-intense lasers provide important scientific research tools.
In application fields related to national strategic needs, such as aerospace safety and aerospace environmental physics, high average power
ultra-intense lasers are important driving tools, with high repetition rate ultra-intense lasers that can adapt to special aerospace environments
as typical examples. Ultra-intense lasers with high repetition rate and high average power produce ultra-intense proton beams, electron
beams, neutron beams, X-rays, gamma rays, and even ultra-intense terahertz pulses. Secondary ultra-intense light sources can serve as new
tools and can be expanded to more cutting-edge major basic scientific research and practical applications such as photonuclear reactions,
laser propulsion, nuclear fusion energy, nuclear waste treatment, and disease treatment.