A140 Different shades of blue?

I just got my second A140 diode and they are visibly different in shade of blue. The first one is a definite BLUE blue, and the second is a lighter color of blue, almost sky blue.

Is there a difference in efficiency and power graphs? Will one be more able to be pushed to higher wattage? Is this a sign of one having more hours of use than the other?

Thanks!

It could just be diode to diode variation.
It also seems that at higher power the wavelength shifts more toward 450nm (bluer and less violet).
Compared to the A130 diode I had and the A140 diode I currently have, the wavelength of the A140 diode is noticeably longer.

The wavelength shift with temperature is extremely small. However there are large variations in wavelength between diodes.

Interesting though, if it's that noticeable and describable as 'sky' blue... Could be off spec but in a fortunate way.

I wish cameras rendered blue differences readily -- they don't... but I don't suppose you could take a shot at well, taking some shots.

Any comparisons you could describe as far as the difference? I don't suppose you've ever seen a 473nm DPSS blue?

I made a thread about this a wail ago and a video.

Thread:
http://laserpointerforums.com/f65/l...y-445nm-lasers-arctic-my-diy-color-58449.html

Video:


In the Video you can see my 1.16W Stainless Steel R2 A140 laser on the Left and in the middle you can see at the time my 758mW Arctic. Then all the way to the right a 201mW red LPC laser.

You can clearly see tha it appears diffrent and my camera picks it up pretty much identical to what you see in real life.

Its due to running them at different currant Just like everyone is saying. The More Currant you give the lighter the blue becomes. The less the currant is the deeper the blue is.

If you run the diodes at the same Currant you will see no difference Minus the wavelength fluctuation if you can even pick that up witch idont think so.

aryntha said:

Interesting though, if it's that noticeable and describable as 'sky' blue... Could be off spec but in a fortunate way.

I wish cameras rendered blue differences readily -- they don't... but I don't suppose you could take a shot at well, taking some shots.

Any comparisons you could describe as far as the difference? I don't suppose you've ever seen a 473nm DPSS blue?

Click to expand...

The display is just as important as the camera.

The camera is more important than the display, plus I don't know of any modern monitor that anyone would actually be using, that wouldn't have sufficient gamut to render color difference great enough that the eye can see as well.

qumefox said:

The camera is more important than the display, plus I don't know of any modern monitor that anyone would actually be using, that wouldn't have sufficient gamut to render color difference great enough that the eye can see as well.

Click to expand...

Theoretically speaking and without any knowledge of current technology, the capture capabilities are just as important as the display capabilities. The chain is only as strong as its weakest link

Practically speaking this is still very true. Many LCDs use a type of dithering known as frame rate control. This allows an increase in the perceived color depth to 24 bits from the actual 18 bits (6 bits per RGB color channel). Most of the LCDs I have seen use dithering. The negative effects of dithering can be seen when displaying a gradient. Dithering should not be considered an accurate representation of true color. This is especially true when examining small differences in the wavelengths of lasers.

Most digital cameras have a similar 8 bits per RGB color channel. However many are also capable of capturing 12 or 14 bits per RGB color channel in the RAW format.

I am not saying one is more important than the other. I am saying they are equally important, and it is necessary to consider the capabilities of both when examining minute differences in laser wavelengths.

I have an a-140 and an m-140, that side beside the m-140 looks purple an the a-140 looks sky blue
Both at 1.3W

Any LCD computer monitor or TV made within the last 5 years is capable of 28bit color depth. (I should kinda know.. considering I repair them for a living..) Only the cheapest of the cheap displays (on cheap chinese mp3 and video players, etc) will resort to dithering to make up for a low actual color depth.

Don't confuse compression artifacts with display limitations. 99.9% of banding and other phenomena like that in displays are due to image/video compression. Not a limitation of the display itself.

Camera's, at least affordable ones, suck at recording blues. They always have. If you don't believe me, Take some pics and load them into image editing software and separate the RGB channels. It probably won't take long to notice the quality of the blue channel sucks compared to the red and green channels. Actually there's a trick to improving images taken with cheap cameras. And that's to apply a slight blur on the blue channel, which does a lot towards getting rid of 'graininess' in images. Especially low light images.

And Jake. I just did a M140 build in a trustfire.. I have it here on my desk. Give me a minute and i'll stick it on the spectrometer. I noticed it was a lot 'brighter' looking than the last 445 build I did but I never measured it.

Ok. Looks like it peaks just short of 448nm when running at 60mW.

Have you checked your a-140? I would love to have a spectrometer, to figure out the 2 exact wavelengths of these, because side by side, in the midnight sky, the a-140 seriously looks like 405, compared to the M-140 which looks like sky blue compared to the a-140

Is it the higher the power you run them at the longer the wavelength? or vice versa?

Generally the higher the power the longer the wavelength... slightly. I don't have any a140's built but I do have some diodes. I'll try to build one next week when I get the next batch of hosts completed.

The one I measured is in a trustfire ef23 running off a AAA.. so it's in no way 'high powered' heh But 60mw off a 1.5v AAA isn't bad.




PS.. Just went back and looked. Aryntha measured one of his a130 diodes previously a while back on this same spectrometer and it showed 446nm. Not sure how noticeable 2nm is going to be, but it's possible your particular diode is on the low side of the curve as opposed to the high side so you could have one that's in the low 440's instead of the high 440's.

Yeah, I wasn't trying to say it was like 430nm and 460nm or anything, but side by side, they are noticeably different wavelengths for sure

And they are both within 100mW of 1.3W

jakeGT said:

Have you checked your a-140? I would love to have a spectrometer, to figure out the 2 exact wavelengths of these, because side by side, in the midnight sky, the a-140 seriously looks like 405, compared to the M-140 which looks like sky blue compared to the a-140

Is it the higher the power you run them at the longer the wavelength? or vice versa?

Click to expand...

According to the data Cyparagon linked to on PL, there seems to be almost no correlation between power output and wavelength.
The difference will mostly be diode to diode variation.

He's talking about current in the same diode. With the same diode, higher current means longer wavelength.