Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



WTB: Radiant x4 or Laserbee 3w

CaliKirk

New member
Joined
Mar 30, 2016
Messages
376
Points
0
Hey there,
I'm currently in need of a new LPM as the Ophir 20c I recently purchased is a little out of calibration. I'm looking to buy a Radiant x4 or a Laserbee that has the ability to measure up to 3w. Ive wanted a more portable LPM and unfortunately I missed the opportunity to pick up an x4 when they were available. Any help would be much appreciated!!!
 



CaliKirk

New member
Joined
Mar 30, 2016
Messages
376
Points
0
Alaskan - thank you for the reply!!! I have been like a moth to a flame on the bay looking for LPM deals. Originally I was looking at buying a new Laserbee 5.2w but would like to try and save some cash. Unfortunately I went a little heavy on the laser purchases this month. :wtf:
 

CaliKirk

New member
Joined
Mar 30, 2016
Messages
376
Points
0
I haven't been able to find a deal on ebay for what you are looking for, but I did find this one which is interesting to me due to its ability to measure close to 30 watts Low Cost Laser Power Meter Molectron PM 30 Head | eBay - portable too, but I don't know how accurate it is.
I was checking those out and contacted that seller a while ago asking about those meters and if they are able to measure in mW increments and the meters they sell only read in .1W increments.

I wish they had a resolution of 1mw because those are a great deal, thanks for checking man! I really appreciate it :bowdown:
 

Attachments

astralist

Active member
Joined
Mar 27, 2011
Messages
503
Points
43
How did you know that your Ophir 20c is out of calibration?? :thinking:
what did you compare it with?
how much % is it off the calibration?
 

CaliKirk

New member
Joined
Mar 30, 2016
Messages
376
Points
0
How did you know that your Ophir 20c is out of calibration?? :thinking:
what did you compare it with?
how much % is it off the calibration?
I guess I don't know 100% if my sensor needs to be recalibrated. I have purchased a used Ophir 20C with a digital MM for the display, and although I can get consistent results from same laser, the sensor itself has what looks to be burn marks from the previous owner.

I have never had the ability to compare to a calibrated LPM. And wanted to purchase another LPM both to compare to my Ophir as well as I'd like to have an LPM that was more accurate with lower powered lasers.
 

astralist

Active member
Joined
Mar 27, 2011
Messages
503
Points
43
Here is some information for you:

  • Fact: Even if the sensor is NIST calibrated, doesn't mean that it will 100% accurate when measuring laser with different wavelength compared to the laser used to calibrated that sensor at NIST.
  • Reason: Because there is no single coating in this world capable of "flat" broadband response. Even for those ophir head, you won't find the spesific spectral response chart because they don't want you to know (unless i'm missing something). AFAIK from their youtube, this type of coating absorbs more at wavelength below 800nm, meaning if it's NIST calibrated on YAG 1064nm with 100mW power reference, it won't give you 100mW when measuring true 100mW 447nm. Instead it'll give you readings above 100mW because of more absorption. The workaround for their product is, they are compensating the reading and user can select if want to measure <800nm or >800nm (this choice exist on their power meter interface, AFAIK). This is also the reason why some OEM design may want you to chose in which wavelength do you need your sensor to be calibrated to.
  • Conclusion: Your sensor will give fairly different reading from its guaranteed calibration, if you are measuring wavelength other than 1064nm, especially if your laser's wavelength is below 800nm (Ophir 20C-A-1-Y is calibrated with "Y" = YAG laser = 1064nm)

One way to roughly check your calibration is by using sunlight, when there is no cloud up sky. It should give 1KW/m². Given your sensor surface area, you can calculate how much its should outputs the volt. This is a really rough method indeed, but at least you can try at home. :beer:
 




Top