Wireless power transmission has become a research hotspot in the field of energy transmission, in which laser power transmission is one of the best methods for long-distance wireless transmission. Since laser has the advantages of high directivity, high energy density and no electromagnetic interference, laser power transmission technology can be applied to the energy supply of unmanned aerial vehicles (UAVs), micro-vehicles, airships and other flight systems. Long-distance laser power transmission can enable high-altitude flight systems to operate continuously without the need to return to the base station for charging, im-proving their operational efficiency. Therefore, high-altitude flight systems have a demand for laser power transmission. However, the commonly used lasers in laser power transmission are semiconductor lasers and fiber lasers, which are only suitable for short-distance transmission of about 1 km. In this paper, taking high-flying UAVs as an example, the transmission efficiency of different lasers used for laser power transmission is analyzed theoretically, and the results show that the diode pumped alkali vapor laser (DPAL) has a high transmission efficiency in high-power long-distance laser power transmission. The transmission efficiency of rubidium lasers which is 1.5 to 4 times that of other lasers can reach 21.94%, which illustrates that DPAL is expected to become a new type of laser source in laser power transmission technology.

A novel double-cycle alternating-flow diode-pumped potassium vapor laser is proposed, theoretically modeled and simulated. The results show that the optical-to-optical efficiency of the laser increases with increasing gas flow rates, although at high flow rates the rate of increase in efficiency decreases. The optical-to-optical efficiency reaches 74.8% at a pump power density of 30 kW/cm² and a gas flow rate of 50 m/s. The optical-to-optical efficiency of the laser is greater with a narrow linewidth pump and high buffer gas pressure. The optical-to-optical efficiency of a flow gas cell is higher than that of a static gas cell. There is an optimal gas cell length that provides the highest optical-to-optical efficiency. At higher pump power densities, higher flow rates are required to obtain higher optical-to-optical efficiencies.

Extending diode-pumped alkali lasers (DPALs) toward high-repetition-rate, high-peak-power burst-mode operation broadens their application potential. Here we report the first experimental demonstration of burst-mode operation in DPALs enabled by high-repetition-rate electro-optic cavity dumping under pulsed optical pumping. The cavity-dumping repetition rate reaches up to 1.2 MHz, representing the highest cavity-dumping repetition rate reported to date for DPALs. The cavity-dumped pulses with a FWHM of 11 ns are generated, delivering a maximum peak power of 96 W. At the highest repetition rate, up to 277 pulses are extracted within a single 250 µs pump period, yielding a maximum total burst energy of 322 µJ. These results verify the feasibility of burst-mode cavity dumping in DPALs and highlight its potential for generating high-peak-power, temporally structured laser outputs.