2.1. What is a laser and how does it work?
What is a LASER?
The laser is a bunch of energy waves (streams of photons called radiation) with the same amplitude and
faze that are flowing in the same direction; meaning they are coherent – they stick together and form a
laser beam.
The width of a single wave is measured in nano-meters and defines the colour and visibility of the laser
beam. The visible spectrum of the human eye is roughly between 400nm and 700nm, going from violet
to a dark red colour. A human eye is most sensitive to a green light of around 555nm, meaning that a 1W
of green laser will always appear more visible than 1W of any other colour laser. 1W of quality laser light
is very powerful and although it doesn’t sound like much it can burn eye retinas, skin and clothes or even
start a fire!
What makes the laser visible?
Mainly it is the particles of dust in the air that the laser beam hits on its path. That’s why we “laserists”
use haze or smoke machines to make lasers more visible. Too much of the haze or smoke will kill it, but
the right amount will make all the difference between no show and a great show.
When outdoors, lasers mainly reflect off dust and mist in the air but due to unpredictable wind conditions
we can never make sure the hazers or smoke machines will be effective enough. And that’s why we use
high power lasers for outdoor shows – to substitute for the lack of dust, haze and smoke.
How far does it go?
Depending on the power output of the system and weather conditions, the laser can be visible for miles –
that is why we need to be cautious about aircrafts when performing outdoor shows. And if you get a
system that is powerful enough then yes, it can reach the Moon.
Colours
Standard full colour analogue lasers use three primary colours: Red, Green and Blue. By mixing those
together you can pretty much get any secondary colour:
Red
+
Blue
= Magenta
Red
+
Green
= Yellow
Green
+
Blue
= Cyan
Red
+
Green
+
Blue
= White
Of course the number and precision of the colours is determined by the modulation, stability and linearity
of the system. If the system is not stable enough, it will produce different colours every time it is used,
making it virtually impossible to match the colours of two systems at any one time. This is very often the
Kvant Lasers s.r.o.
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