W/cm^2 to Joules conversion?

[xanatos]

I need to convert some laser power specs. For the sake of convenience, let's say I have a 1 Watt 445nm laser irradiating exactly 1 square centimeter.

Question 1: Does this represent, properly, 1W/cm^2 ?

Question 2: if Q1 is correct, how would I convert that to joules per cm^2?

If Q1 is incorrect in assumption, how do I figure irradiance per cm^2 based on my measured output power in mW?

Much appreciated! Thanks,

Dave

 

[Trevor]

Q1 is correct.

Watts per centimeter squared means joules per second per centimeter squared.

Joules represent energy, watts represent watts per second. Watts times seconds gives you joules.

-Trevor

 

[Xtrm2Rick]

correct me if im wrong but iirc it was something like this:

1 joule = 1W/s... or was it the other way around:undecided:



aw im to slow... nicely explained Trevor

 

[Trevor]

Yeah, power is energy over time - power is watts and energy is joules.

Some people refer to a joule as a "watt-second" though, referring to 1W*1s.

-Trevor

 

[xanatos]

Perfect... I thought time factored in there somewhere. Thanks very much!

 

[DrSid]

Well not trying to be rude, but wikipedia has great articles on physics. You should try it .. or google, generally it will point right there.

 

[Mo13]

Q1 is correct.

Watts per centimeter squared means joules per second per centimeter squared.

Joules represent energy, watts represent watts per second. Watts times seconds gives you joules.

-Trevor

He means watts represents joules per second. That's just a typo.

correct me if im wrong but iirc it was something like this:

1 joule = 1W/s... or was it the other way around:undecided:

Yeah, power is energy over time - power is watts and energy is joules.
-Trevor

Actually no, it's the other way around, as in: 1W = 1J/s, but everything he said after that is absolutely correct!



I kinda feel like a jerk for correcting you guys, but I'd hate to see a project fail over something so silly. :beer:

BTW, I LOVE the title to this thread. (I know, I'm a total geek.)