im kinda new to lasers but would really like to understand them.

[seth jones]

i don't really know allot about lasers apart from i really like them. could someone please explain to me what (nm) is? and i always thought that the more MWs a laser has the brighter the beam and light will be but I've just seen some vids of people with a 5MW laser and its bright as hell. ?????

thanks

 

[Sigurthr]

Welcome!

A few quick run downs for you;

nm or nanometers is a measure of wavelength, which determines the color of the laser. Normal human vision is somewhere in the range of 360-860nm. Above 700nm is Infrared (invisible) and below 400nm is ultraviolet (invisible). Note that the ranges in my last sentence are marked as invisible but many folks such as myself can indeed see much of them. 400-700nm is the conservative scale that everyone can see, 360-860nm is the complete scale. Look up the wiki article for wavelength or visible light for more info.

Don't use "MW" it will piss people here off. "mW" is correct, note the little m it is important. It stands for miliwatts or 1/1000th of a watt. It is a measurement of how much energy is being released as light by the laser, nothing more.

Human vision sees wavelengths near 555nm as brighter than anything else, even if the output power (mW) is the same between them. For example 5mW of 589nm is MUCH brighter than 5mW of 405nm (hard as hell to see) or 780nm (invisible to 25% of the population) or 5mW of 660nm (the standard red laser pointer wavelength). Moving from 660nm to 635nm and keeping 5mW you end up with a much brighter laser, but the color is now tinged with orange. Understand?

Also, because any laser pointer over 5mW is illegal to sell in most western countries, people mark their lasers as 5mW when they are really not. It is not uncommon for a laser marked as 5mW to be up to 100mW in output, sometimes as a mixed output of visible and invisible light (when the laser is green).

Now that you understand the units it will be easier to search (manually, not necessarily with a search function) the info you'll need here on the site. Happy reading and safe lasing (wear goggles when using >5mW lasers!).

 

[seth jones]

thanks man :beer: