The petawatt laser facility has a significant influence on specific research fields, such as particle acceleration, secondary particle source generation, inertial confinement fusion, and radiotherapy. Until 2020, over100 petawatt laser facilities have been proposed and under construction worldwide. In order to promote the development of ultrafast laser science and applications, the access is opened to the advanced fundamental laser facilities to researchers and technical supports are provided, petawatt laser facilities are managed by different local organizations, mainly located in North America, Europe and Asia. Based on the high power laser organizations in the world, the technical route, the laser parameters and the relevant technologies of the compact high-intensity ultrashort petawatt laser facilities are proposed.

All-solid-state dual-wavelength lasers are widely used in differential absorption lidar, precision measurement, biomedicine, terahertz generation, etc. Dual-wavelength lasers can be obtained through direct generation in single and dual laser gain media based on stimulated radiation, or laser pumped optical parametric oscillators. The main technical approaches and developments on dual-wavelength laser generation are introduced. The methods to tune the power ratio between two wavelengths and manipulate the pulse operating mode are summarized. The merits and demerits of these methods are analyzed, and the outlook is also given.

All-solid-state pulsed lasers play an important role in medical， military， industrial and scientific research fields for its high energy and short pulses. Passive Q-switching and mode-locking are the two most effective techniques for generating all-solid-state pulsed lasers. Among them， the saturable absorber is the key device that has a great influence on the laser output parameters. In recent years， novel low-dimensional material saturable absorbers represented by carbon nanotubes， graphene， and black phosphorus have been widely studied due to their convenient preparation process， low fabrication cost and wide optical response bandwidth. The research progress of some novel saturable absorber materials such as novel transition metal dichalcogenides， ternary chalcogenides， MXenes， single-element alkenes and low-dimensional nanostructures is reviewed in all-solid-state pulsed laser modulation. The future development of novel low-dimensional material saturable absorbers is also prospected.

A scheme to generate high-efficiency terahertz (THz) wave based on cascaded difference frequency generated in a periodic polarized lithium niobate (PPLN) crystal with an optical parametric oscillator is presented. By optimizing the reflectivity of the resonator mirror, Stokes photons oscillate in the cavity, while anti Stokes photons pass through the cavity only once. All the Stokes photons propagate from the left side of the cavity to the right, which ensures that all the Stokes photons pass through the PPLN crystal in one direction. Every time the Stokes photons oscillate in the cavity, the photons of the pump waves are transferred to the Stokes photons. The Stokes processes are enhanced and the anti-Stokes processes are depressed simultaneously. The energy conversion efficiency from pump wave to THz wave reaches 21.2% with pump wave intensity of 10 MW/cm2 and signal wave intensity of 0.01 MW/cm2 at 100 K operation temperature. The above efficiency exceeds the Manley-Rowe relation, which provides an optimal scheme for generation of high efficient pulse, quasi-continuous, continuous THz waves.

Based on the physical conditions of single-frequency operation of lasers, the relationship between the transmissivity of output coupling mirror corresponding to the critical single-frequency operation of high-power laser and the injection pump power is theoretically simulated and analyzed. According to the theoretical simulation results, the output coupling transmissions for the laser with end-pumped single laser crystal and a pump power of 115 W, as well as for the laser with double end-pumped two laser crystals and a total pump power of 240 W, are optimized to be 25% and 37%, respectively. As results, single-frequency continuous wave 1 064 nm lasers with output powers of 51 W and 101 W are realized separately in a single resonator, with respect to the optical-to-optical conversion efficiencies of 45.9% and 42.9%, respectively. Experimental results are consistent with the theoretical expectation.

The hazards of stimulated Raman scattering (SRS) to intense laser systems are introduced, mainly including stimulated rotational Raman scattering (SRRS) generated by intense lasers during long-distance transmission in air and transverse stimulated Raman scattering (TSRS) in large-aperture KDP crystals. It is shown that SRS not only loses laser energy and reduces beam quality, but TSRS may also damage KDP crystals. To address the harm of SRS to the intense laser system, the main suppression schemes of SRS is introduced at home and abroad, the new idea of reducing the SRS gain by controlling the polarization direction is also focused on.

Controlled wavelength pulses have widespread applications in the fields of telecommunications, biomedical research, metrology, and laser processing. A wide wavelength tunable all-normal-dispersion femtosecond ytterbium-doped fiber laser is designed based on nonlinear polarization rotation with an intracavity birefringence induced spectral filter. Taking advantage of the intracavity-birefringence induced spectral filtering effect, the center wavelength of the mode-locked femtosecond pulse can be continuously tuned from 1 015 nm to 1 075 nm by properly rotating wave plate and adjusting angle of birefringent filter. Over the tuning range, it delivers pulses of 4.52 ps duration at a repetition rate of 25.6 MHz and an output power of 85 mW.

A solid-state high-power 318.6 nm ultraviolet laser system is introduced, which generates a 637.2 nm single-frequency laser by single-pass PPMgO:LN crystal sum-frequency generation of two infrared lasers at 1 560.5 nm and 1 076.9 nm, then generates 2 W narrow-linewidth continuously-tunable 318.6 nm ultraviolet laser by a four-mirror ring cavity second-harmonic generation of 637.2 nm laser. Based on the laser system, closed-loop feedback intensity stabilization of 318.6 nm ultraviolet laser is carried out with acoustic-optic modulator(AOM). The fluctuation of laser intensity in time domain is suppressed from ±11.12% to ±0.08% , and effective bandwidth of feedback loop in frequency domain is about 13 kHz. Trap-loss spectroscopy of cold cesium atoms is demonstrated by combining ultraviolet laser with cesium magneto-optical trap. It is of great importance to obtain a stable, narrow-linewidth, continuously-tunable 318.6 nm ultraviolet laser for the study of interaction between cesium Rydbergatoms.

A self-starting picosecond Ti:sapphire laser pumped by 465 nm blue laser diodes is introduced. A double-side pumping structure is adopted in the laser, which makes up for the lack of mode matching and makes full use of the Ti:sapphire crystal with low doping concentration and long optical length. When the pump power is 7 W, a continuous wave output power of 718 mW is achieved and no obvious pump-induced loss phenomenon is observed. With the assistance of semiconductor saturable absorber mirror (SESAM), the self-starting passive mode-locking output of 371 mW and 6 ps is obtained, and the RMS value of the output power is less than 0.5% within 10 hours.

A dual-wavelength solid-state laser with high repetition rate and narrow pulse width at 1 064 nm and 532 nm line of electro-optical Q-switched and master oscillator power-amplifier (MOPA) technology is introduced. Using Nd:YVO4 crystal as laser gain medium and electro-optical Q-switched, the 1 064 nm local oscillator laser output is obtained, In order to obtain stable pulse laser output, on the basis of the local oscillator level of the laser, the two-stage traveling wave amplification is carried out. When two-stage amplified pump current is 6.7 A and the repetition rate is 10 kHz, the output power is 31.4 W and the pulse width is 6.2 ns. The power stability root mean square (RMS) is 0.25 %. The output power of 16.6 W 532 nm laser is obtained by extra-cavity double-frequency. The conversion efficiency from 1 064 nm fundamental light to 532 nm frequency doubling is 53%.