How to make a laser pointer

Without laboring the point , just to put some rough numbers on the power of some of these laser pointers..

The suns energy on the Earths surface is about 1kW per square metre

A 240mW laser pointer has a spot size of say 1mm2, so multiply this by 1,000,000mm2 to get the energy per square metre = 240kW/m2

The light rays from the laser are parallel so when they hit the lens of your eye, the 1mm2 laser spot will be focused down to a spot much smaller than this on your retina with exactly the same energy (say a tenth the spot size), so the radiance on the back of your eye is ten times this, say 2400kW/m2. Ouch !!
This is where the danger begins as the lens in your eye focuses the energy into an even smaller spot size but with the same punch behind it.

The math might be wrong but I think you get my point. Discussion closed.

More than one million people died in traffic accidents last year.

Around 80 Irish people died by falling down their stairs.

No one on Earth was recorded as having been hurt by any laser pointer.

Might as well be scared of Leprechauns.

Peter.

Might as well be scared of Leprechauns.

Those little B*****DS scare the be-jasus out of me.
Just imagine the damage one of those feckers could do with a home made laser pointer! :shock:

Might as well be scared of Leprechauns.

Those little B*****DS scare the be-jasus out of me.
Just imagine the damage one of those feckers could do with a home made laser pointer! :shock:

t'would be a well defended pot o' gold, to be sure to be sure

No one on Earth was recorded as having been hurt by any laser pointer.

WRONG

I climbed into the car with one in my back pocket which broke and I cut the ass of myself :lol:

No one on Earth was recorded as having been hurt by any laser pointer.

WRONG

I climbed into the car with one in my back pocket which broke and I cut the ass of myself :lol: