looking for a cheap laser power meter

[White-Light]

If I remember correctly from the ILDA site audience scanning documents an exposure of 5-10mw per cm² is always considered to be safe without calculations (for a non static beam). However to measure it you obviously need a fast response sensor (to keep up with the scan speeds) that has a 1cm² sensor. However these meters are currently mega $ £ etc.

BTW anyone received anymore news on scanguard software?

[lasersbee]

Cheaper than most but they're still not what I'd call cheap. Wonder what it is that makes laser meters so expensive when multimeters are a few pounds.

Also, its a pity nobody makes a cheap exposure meter to ILDA standards as this is the only way to guarantee audience safety.

Personally I just wish someone made a dual meter that was cheap (less than £100) so both power and exposure per cm² were combined in 1 meter.

Before we designed the LaserBee I the cheapest LPM was the Optical
Sensor LaserCheck at around $500.00 shipped.. I even bought one..
It's useless for stable 405nm readings...

And a thermal based meter under $1000.00 was rare... and people were
saying... If only someone could design a Thermal LPM for under $400.00..
So we did.... we cut the targeted price in half..

If LPMs could be built for a few dollars.... there would still be people saying
they are too expensive... and someone should design a cheaper one...
I guess that the only way to prevent that is to give them away..IMO...

Jerry

[buffo]

Excuse me, Jerry? A Coherent LaserCheck is useless for stable 405 nm readings? I must respectfully disagree.

I've had a LaserCheck for a little over 3 years now. I paid $330 for it (including shipping), direct from Edmund Optics. I've used it to measure numerous 405 nm diodes up to 100 mw (along with lots of other lasers all the way up to a watt) and I've never had any problems with repeatability.

Granted, a thermal power meter is more versatile, since you don't have to change the wavelength setting for different lasers. But nevertheless, my LaserCheck has been one of the most useful tools I've ever purchased. Also, it came with a certificate of calibration that listed the standard that was used, in case you needed tracing information for your lab records. That sort of pedigree doesn't come cheap.

I agree that your meter is cheaper, and the data logging feature *is* nice, but I can't understand why you'd be so critical of the LaserCheck, especially when has been such a popular standard for so many years.

Adam

[White-Light]

Didn't mean to sound harsh Jerry, its just that whilst yours is perhaps one of the cheapest, laser meters are still not cheap by many people's standards. Maybe there's some very expensive component used in power meters that justifies this, I don't know. Its just laser meters seem expensive when compared to virtually any other type of meter out there and given that safety and known power levels go hand in hand, I personally don't see the lack of an accurate but VERY cheap meter as a good thing. I'm sure for the money, yours are excellent value. Its just a pity that they can't be manufactured more cheaply than they are.

[Laserman532]

all power meters, no matter who makes them may only be used as a reference and not as a accurate reading, unless the meter is calibrated at least annually to a know NIST traceable standard.

I know that the back of my hand starts to feel pain at around 500 mw in a few seconds, but I would not call that "power measurement" NIST traceable.

The lasercheck is a great instrument, but as usual I feel it should be cheaper, but technially after a year it is only a guide and not tracable. The laserbee with its data logging feature is a good deal at his list price, now is it tracable

I have an Ophir 300 watt meter i use for my big yags, it is out of callibration so my readings are only a ballpark figure...until it is callibrated.

FYI- we use to use turkey thermometers as a reference for quick measurements of high power lasers - never underestamate the power of a simple concept of rate of change in particular materials

[lasersbee]

Didn't mean to sound harsh Jerry, its just that whilst yours is perhaps one of the cheapest, laser meters are still not cheap by many people's standards. Maybe there's some very expensive component used in power meters that justifies this, I don't know. Its just laser meters seem expensive when compared to virtually any other type of meter out there and given that safety and known power levels go hand in hand, I personally don't see the lack of an accurate but VERY cheap meter as a good thing. I'm sure for the money, yours are excellent value. Its just a pity that they can't be manufactured more cheaply than they are.

I wasn't offended by what you said... I understood you point..
When I was younger there were no DMMs but analog VOMs.. and an the
inexpensive ones were over $100.00... Today they make DMMs by the
truckload and you can pick one up for under $5.00
Hopefully.. in the near future we can get a decent LPM for under $100.00..

Jerry

[lasersbee]

all power meters, no matter who makes them may only be used as a reference and not as a accurate reading, unless the meter is calibrated at least annually to a know NIST traceable standard.

I know that the back of my hand starts to feel pain at around 500 mw in a few seconds, but I would not call that "power measurement" NIST traceable.

The lasercheck is a great instrument, but as usual I feel it should be cheaper, but technially after a year it is only a guide and not tracable. The laserbee with its data logging feature is a good deal at his list price, now is it tracable

I have an Ophir 300 watt meter i use for my big yags, it is out of callibration so my readings are only a ballpark figure...until it is callibrated.

FYI- we use to use turkey thermometers as a reference for quick measurements of high power lasers - never underestamate the power of a simple concept of rate of change in particular materials

The LaserBee I is marketed as a Hobbyists 1 Watt Thermal Power meter..
an it is not NIST traceable...
We calibrate each LaserBee I to its Serial numbered Thermopile using a
Newport 1825-C with an 818T-10 Thermopile Head on the same day it
leaves the shop..
Companies like Coherent calibrate the Thermopile head its self...
We calibrate... (because of the variations that can occur in manufacturing)
the Thermopiles...by the PCB electronics and Firmware..

I agree with you that if you want to be 100% accurate.. you would need
to spend mucho $$$$ and need frequent re-calibrations..
But for hobbyists... I think.. even just a few mW off is still close enough
for what the hobbyist needs to do with an affordable LPM.

BTW... we have built into the LaserBee I Firmware... a Re-Calibration
routine that you could re-calibrate the LaserBee I to a know calibrated
LPM yourself..
You are not forced to send it back to us for recalibration like the
LaserCheck... but we do offer the service if you can't do it yourself...

Jerry