445 experiments

[stanwax]

heres something to consider when measuring power straight off the unit - ie not driving it directly, the blue lasers are gated on and off at 250hz @ 50% duty cycle
see attached
So measurments with the likes of Coherent LC are not to be truusted (not that LC is too good at shorter wavelengths anyway)
Also a close up of one of them cuties....plus obligitory laser canon shot sans fog.

Rob

[andy_con]

heres something to consider when measuring power straight off the unit - ie not driving it directly, the blue lasers are gated on and off at 250hz @ 50% duty cycle
see attached
So measurments with the likes of Coherent LC are not to be truusted (not that LC is too good at shorter wavelengths anyway)
Also a close up of one of them cuties....plus obligitory laser canon shot sans fog.

Rob

so what your saying rob is, if a power meter is reading 700mw as they have a 50% duty cycle we could actually be looking at 350mw per diode?

roughly speaking?

[smogthemog]

Other way around Andy isn't it?

1.4Watts??

[norty303]

so what your saying rob is, if a power meter is reading 700mw as they have a 50% duty cycle we could actually be looking at 350mw per diode?

roughly speaking?

Actually I think its the other way around, the Coherent LC can't respond fast enough to the 'off' cycles and so measures an average lower reading than what the peaks really are.

The same way that a thermopile isn't any good for measuring a scanned pattern.

What Rob might be implying is that they are run hotter than 1w but only for 50% duty!


Does that make these unit pulsed then?

[stanwax]

Jim is more right but the reading wont be double unless the meter is designed to measure transient output but especially with an LC as its readings are barmy at the best of times and its for CW measurments only. I am gonna look to see if I can finf the 250hz clock and defeat it breifly to get a cw reading.....watch this space.
My old (uncalibrated) sensor physics meter is reading >850mW but LC reads 520mw on the same diode
I will report back when I get CW

Rob

[andy_con]

my bad, yep yep.

[stanwax]

What Rob might be implying is that they are run hotter than 1w but only for 50% duty!

Kinda - I think they are gonna be 1w diodes I just think that we need to be carful in taking readings right off the unit while its gating

Rob

[mccarrot]

Respect to all of you testing these new baby's!

[sbk]

So measurments with the likes of Coherent LC are not to be truusted (not that LC is too good at shorter wavelengths anyway)

When I measure my 1W 445nm with my Lasercheck, the power meter reacts strangely... First I can't see the full 1W on the display (it starts at 800mW), and then it progressively decreases the displayed power down to 5-600mW after a few measurements. So I think the Lasercheck display a too low value comparing to the real power, maybe due to a too big energy directed to the sensor?

[stanwax]

I would agree SBK its the photodiode that does not respond well to the shorter wavelengths - its crazy when you try it with 405 too...

Rob