A picture of my (powered on) 450mW high-power green (532nm light wavelength) DPSS laser. Despite the fact that this picture was shot in light, the laser beam is still clearly visible due to dust in the air and Rayleigh scattering.
The laser itself is resting on my rather cluttered desk. Visible in the background is my watch, which I was using to time the powered-on time of the laser, which is rated for 100 seconds on then 60 seconds off.
For some reason, my camera decided to focus slightly behind the laser, hence why the laser aperture itself is out-of-focus.
See also another laser shot of mine, particularly, the same laser, but in the dark.
DANGER: The laser shown here is a class 3B laser device. Class 3B lasers areNOT laser pointers, and should never be used for that purpose. Despite the fact that I took the picture with the laser sitting on my desk, and despite the fact that I seem to have fun when using my lasers (I do), I took proper safety precautions to ensure that myself and others do not get injured; for example, I wore ANSI Z87.1-standard green laser safety goggles at all times when the laser was operating.
In other words, unless you know what you're doing, DO NOT TRY THIS AT HOME. You could inadvertently blind yourself or someone else. And, of course, high power laser devices should NEVER be pointed at other people, and lasers of any kind should NEVER be pointed at aircraft, especially those in flight. High-power lasers like this one should be treated with the same respect as you would treat a loaded gun.
Please be aware that high power laser devices may be restricted by laws in your area.