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



New Sanwu 150 mW Challenger2-Photos of LED Color-White Balance settings

Pelagius

Active member
Joined
Jul 1, 2018
Messages
292
Points
43
I am in no way challenging Sanwu. It was marked 492 on the wrapping. Paul was thinking it looked more like 488 and I know he has compared many of these diodes.
But perception and photography are both fickle! I'd call this aquamarine.
So I set my Canon 5D MKIV on RAW, took the laser lens off and shined it on white paper-in indirect sunlight- took a picture of the paper by itself-then the led shined on the paper. I used Photoshop to White Balance- gave color temperature reading as between 6400 and 6300 K.
So here are shots of the paper- and the LED on the paper. The paper could be used for WB for anyone interested to make sure they are seeing what I am seeing.

If a mod wants to move this to my review thread-that's fine. My purpose is related to figuring out if it's really a 492 nm. I'm almost certain the only way is to buy a spectrophotometer measured 488 to compare-or a Laser Spectrophotometer.
Edit: on my screen the image is very close to what I see. Your monitor may vary-which is why I included the paper shot for White Balance/Color temperature adjustment
I'd also like a manufacturer to make a 200 mW+ version @ 493-495 nm- 1 Watt is acceptable
:)
 

Attachments

Last edited:

BowtieGuy

Well-known member
LPF Site Supporter
Joined
Oct 14, 2012
Messages
5,680
Points
113
I'll bet one of the guys here that have a spectrometer would check that wavelength for you, then you'd know for sure. :yh:
 

paul1598419

Well-known member
Joined
Sep 20, 2013
Messages
14,938
Points
113
Sure. I'd be happy to measure it for you. That is really the only way you will ever know for sure. If you are interested, send me a PM and I will give you my address. :yh:
 
Last edited:

BowtieGuy

Well-known member
LPF Site Supporter
Joined
Oct 14, 2012
Messages
5,680
Points
113
Hey Paul, I figured you'd be the first to step in and volunteer to verify the wavelength of his 492nm? Sanwu. :yh:
 

paul1598419

Well-known member
Joined
Sep 20, 2013
Messages
14,938
Points
113
Yeah, I'm always here to help anyone whenever I can. I need to send you a PM about something you might be able to do for me, Jeff. I will take care of that now. :yh:
 

steve001

Well-known member
Joined
Jun 3, 2007
Messages
2,253
Points
83
I am in no way challenging Sanwu. It was marked 492 on the wrapping. Paul was thinking it looked more like 488 and I know he has compared many of these diodes.
But perception and photography are both fickle! I'd call this aquamarine.
So I set my Canon 5D MKIV on RAW, took the laser lens off and shined it on white paper-in indirect sunlight- took a picture of the paper by itself-then the led shined on the paper. I used Photoshop to White Balance- gave color temperature reading as between 6400 and 6300 K.
So here are shots of the paper- and the LED on the paper. The paper could be used for WB for anyone interested to make sure they are seeing what I am seeing.

If a mod wants to move this to my review thread-that's fine. My purpose is related to figuring out if it's really a 492 nm. I'm almost certain the only way is to buy a spectrophotometer measured 488 to compare-or a Laser Spectrophotometer.
Edit: on my screen the image is very close to what I see. Your monitor may vary-which is why I included the paper shot for White Balance/Color temperature adjustment
I'd also like a manufacturer to make a 200 mW+ version @ 493-495 nm- 1 Watt is acceptable
:)
There's an accurate way for determining wavelength by using a diffraction grating and a laser of known wavelength. YouTube to see how.
 

Pelagius

Active member
Joined
Jul 1, 2018
Messages
292
Points
43
Thanks Paul!
Sure. I'd be happy to measure it for you. That is really the only way you will ever know for sure. If you are interested, send me a PM and I will give you my address. :yh:
HEHE BowtieGuy
Hey Paul, I figured you'd be the first to step in and volunteer to verify the wavelength of his 492nm? Sanwu. :yh:
Yeah, I'm always here to help anyone whenever I can. I need to send you a PM about something you might be able to do for me, Jeff. I will take care of that now. :yh:
Steve! Thanks for reminding me. Something about a diffraction grating and measuring the distance between dots on the wall. I'll look into that!

There's an accurate way for determining wavelength by using a diffraction grating and a laser of known wavelength. YouTube to see how.
I'm pretty sure I'll keep it-either way. :)
 

paul1598419

Well-known member
Joined
Sep 20, 2013
Messages
14,938
Points
113
If you already have a diffraction grating you can do this much easier than using a CD as a grating. But, your setup will be critical. So, measure the wavelengths of some HeNe and DPSS lasers to ensure the quality of your setup.
 

Pelagius

Active member
Joined
Jul 1, 2018
Messages
292
Points
43
Hi Paul
I was looking on EBAY for diffraction gratings- they sell many- rated at 1000 lines/mm and above. Ideally, I am hoping for a handful of dots to measure-unless I am misunderstanding what the 1000 lines/mm rating means. :)
I did try reflecting off the back of a CD. Nice dots. Just have to get clams so I can hold it steady while I measure. I have a few DPSS (532 nm)- no HeNe lasers. An excuse to get a yellow? :) Yikes! 589 DPSS 50 mW $400! Maybe I'll wait for a price drop. I'd feel better with 2 reference measurements. I guess I'll do 5 independent 532 nm ,measurements to check my personal % SEM!

I see these from Dragon Lasers
https://www.dragonlasers.com/Laser-Beam-Splitters.html


If you already have a diffraction grating you can do this much easier than using a CD as a grating. But, your setup will be critical. So, measure the wavelengths of some HeNe and DPSS lasers to ensure the quality of your setup.
 
Last edited:

steve001

Well-known member
Joined
Jun 3, 2007
Messages
2,253
Points
83
Hi Paul
I was looking on EBAY for diffraction gratings- they sell many- rated at 1000 lines/mm and above. Ideally, I am hoping for a handful of dots to measure-unless I am misunderstanding what the 1000 lines/mm rating means. :)
I did try reflecting off the back of a CD. Nice dots. Just have to get clams so I can hold it steady while I measure. I have a few DPSS (532 nm)- no HeNe lasers. An excuse to get a yellow? :) Yikes! 589 DPSS 50 mW $400! Maybe I'll wait for a price drop. I'd feel better with 2 reference measurements. I guess I'll do 5 independent 532 nm ,measurements to check my personal % SEM!

I see these from Dragon Lasers
https://www.dragonlasers.com/Laser-Beam-Splitters.html
The more lines per millimeter the greater precision will be gained. Another way i believe for greater still precision is to use a Youngs double slit. See here. https://youtu.be/uhNylYhg-YY
 

paul1598419

Well-known member
Joined
Sep 20, 2013
Messages
14,938
Points
113
I believe the 1000 l/mm are for greater accuracy than precision. Precision is the ability to get the same result many times over using the same laser and setup. I bought a large sheet of 1000 l/mm that is 20 cm^2. I have had no use for it since getting my first spectrometer. I have cut sheets out of it and mailed them to members here that want to use a grating to measure wavelengths.
 
Last edited:




Top