How many times is the laser brighter than the sun?

Before the invention of laser, the brightness of high-voltage pulsed xenon lamp in artificial light source is the highest, which is equivalent to the brightness of the sun, while the laser brightness of ruby laser can exceed tens of billions of times that of xenon lamp. Because the brightness of laser is extremely high, it can illuminate distant objects. The illumination produced by ruby laser beam on the moon is about 0.02 lux (illumination unit), the color is bright red, and the laser spot is obviously visible. If the strongest searchlight is used to illuminate the moon, the illumination produced is only about one trillionth lux, which is impossible for human eyes to detect. The main reason of high laser brightness is directional light emission. A large number of photons are emitted in a very small space, and the energy density is naturally extremely high.