Sanwu 488nm vs 492nm?

[hxdrummerxc]

Hey All,

It's been a while since I've posted on these forums. I've been inactive for a little. (Couple of years) Still enjoying the lasers that I have had all the time. I just got to a point in life where other things took financial priority. (You know, Marriage, house, etc etc lol)

I "left" not long after the 445nm diode from nichia came out and the "blue" laser was finally affordable. I built one and loved it (still do). But just about any other wavelength of blue at the time was way to expensive.

Well I just randomly decided to check the forums only to see that some of these wavelengths have become more affordable.

Looking at the Sanwu 488nm 55mW or 492nm 100mW. What would be the advantages/disadvantages?

I have been out of the "game" so long, I don't know anything about these diodes and what their pattern is like etc.

I really like these Sanwu and this cyan color wavelength. In my mind 488-492 isn't that much of a difference and 100mW would probably be a lot brighter/more visible and the price difference is not much at all. Anyone have a beam comparison of 488-492?

Thoughts/recommendations?

 

[paul1598419]

They are both Sharp diodes, so the only real difference, besides the wavelength, is the current they are driven at. To get 100 mW out of a 492nm Sharp diode, you need to drive them at 250 mA or more. The 488nm ones are just binned diodes from the same batch and since the heat sink is tiny and insignificant, these diodes are driven at about 75 mA. With the 30 second run times, you will likely not see much of a shift up in wavelength.

 

[ZRaffleticket]

Here's 485 vs 488 vs 492 vs 495, on my sRGB screen to my eyes:

 

[LewDude]

Very nice representation, ZRT. Between Paul's written and ZRT's visual, I think that should give you a good idea of what you can expect. I made a small post with some beam shots, if it helps (BUT the 490ish is NOT putting out 100mw): https://laserpointerforums.com/f48/488nm-vs-49xnm-102817.html

 

[Gazen]

There’s a decent different between the 2, my sharp 485(really >490nm) appears green at night, while others(<490nm) are almost completely blue. I would go with the 488 personally.

The pockets are really great with nice threads and tiny size, you can’t go wrong with one.

Edit: My “485” is really >490nm

 

[paul1598419]

Very nice representation, ZRT. Between Paul's written and ZRT's visual, I think that should give you a good idea of what you can expect. I made a small post with some beam shots, if it helps (BUT the 490ish is NOT putting out 100mw): https://laserpointerforums.com/f48/488nm-vs-49xnm-102817.html

The amount of power you can get out of one of these diodes depends on several conditions. You will need to drive it ~250 mA and chose your lens wisely. If you use a 3 element lens you should expect to lose up to 30% of your power over a single element aspheric lens. But, with a asphere you will also get a refection artifact that is rectangular in shape to the side of the dot.

I use the acrylic lenses on mine as I don't see the rectangular artifact with them and you lose less power than the 3 element lenses. I recently got a chance to try one of DTR's 2 element 520nm AR coated lenses, and to my surprise I didn't see the artifact with that lens either. It was the first glass lens I have used that didn't have it on any of my Sharp diode builds. From 477nm up to 507nm.

I recently purchased four of them from Jordan to use in place of the acrylics because the housings on the acrylic lenses are too short and to use one you need to fix it in place just as it catches the threads. I use fingernail polish to do this.

You put it on the threaded side of your focus ring of knob and turn the lens until it just catches. Then pull on the lens and set it upside down for a hour or two to dry. But, you then have to use the weaker spring as the higher tension one will break the polish loose. I use fingernail polish because if you need to start over for any reason, acetone will remove all traces of it. But, don't get it on the acrlic lens as it will melt it. :yh:

 

[Encap]

Here's 485 vs 488 vs 492 vs 495, on my sRGB screen to my eyes:

Excellent photo comparison. +rep when I can.

There’s a decent different between the 2, my sharp 485 appears green at night, while others are almost completely blue. I would go with the 488 personally.

The pockets are really great with nice threads and tiny size, you can’t go wrong with one.

485nm green?

If your 485nm appears green it can't really be 485nm, 485nm is blue by definition, the actual definitions of spectral range color names, or it is due to your particular eye's visual response--maybe a reduced ability to see blue or some other factor.
No system anywhere at any time has ever put 485nm in the color called "green" spectral range.

Did you have it's wavelength tested and confirmed by a spectrometer?

 

[Gazen]

Excellent photo comparison. +rep when I can.



485nm green?

If your 485nm appears green it can't really be 485nm, 485nm is blue by definition, the actual definitions of spectral range color names, or it is due to your particular eye's visual response--maybe a reduced ability to see blue or some other factor.
No system anywhere at any time has ever put 485nm in the color called "green" spectral range.

Did you have it's wavelength tested and confirmed by a spectrometer?

I meant 490, it’s called 485 on the sharp data sheet, but they Spectro 486-494. Mine is one of the higher wavelength ones. It has not been tested with a spectrometer.

 

[hxdrummerxc]

You guys are awesome! Thanks for the quick responses.

I really like the more cyan tint that the 492+ puts out in these pictures. I actually think that I would prefer the more cyan color over a light blue.

Is 55mW (give or take) enough to see a good beam at 488nm? I have never had anything near this wavelength. I know your standard green laser beam would be visible at 55mW. However, the 445nm that I have probably wouldn't have much of a visible beam at 55mW.

I am just imagining the beam visibility being much better on 100mW of 492nm.

Hmm decisions decisions

 

[Gazen]

You guys are awesome! Thanks for the quick responses.

I really like the more cyan tint that the 492+ puts out in these pictures. I actually think that I would prefer the more cyan color over a light blue.

Is 55mW (give or take) enough to see a good beam at 488nm? I have never had anything near this wavelength. I know your standard green laser beam would be visible at 55mW. However, the 445nm that I have probably wouldn't have much of a visible beam at 55mW.

I am just imagining the beam visibility being much better on 100mW of 492nm.

Hmm decisions decisions

The 55mW should give a decently visible beam, at least from the eye of the holder. Use this calculator to compare beam visibility:

Relative Laser Beam Brightness Calculator: (589nm 5mw) vs. (490nm 5mw)

 

[ZRaffleticket]

I tuned down the current on my labby setup to ~55mW and ~100mW. 55mW is visible in a well lit room facing me. At night it'll be easy to see outside, though tonight it's foggy and anything I do will be skewed





And got a nice beam shot of 488, 492, and 495

 

[paul1598419]

The 55mW should give a decently visible beam, at least from the eye of the holder. Use this calculator to compare beam visibility:

Relative Laser Beam Brightness Calculator: (589nm 5mw) vs. (490nm 5mw)

The thing here is that a 589nm at 5 mW is possible for ~$400, but the 490nm is very doable at 100 mW for about $100. Check the relative visibility of 589nm at 5 mW against 490nm at 100 mW. No contest.

 

[hxdrummerxc]

So, since these diodes tend to vary per individual diode. Does anybody know if Sanwu actually tests them? Or do they just use one of these diodes and label it 488nm?

I'm just curious if it's possible that their "492nm @ 100mW" and their "488nm at 55mW" is tested anyways.

So let's say, is it possible to order the "492nm @ 100mW and end up with a diode that's putting out closer to 488. Or vice versa?

 

[steve001]

You guys are awesome! Thanks for the quick responses.

I really like the more cyan tint that the 492+ puts out in these pictures. I actually think that I would prefer the more cyan color over a light blue.

Is 55mW (give or take) enough to see a good beam at 488nm? I have never had anything near this wavelength. I know your standard green laser beam would be visible at 55mW. However, the 445nm that I have probably wouldn't have much of a visible beam at 55mW.

I am just imagining the beam visibility being much better on 100mW of 492nm.

Hmm decisions decisions

Know your colors. Cyan is a range of blues. Light blue is cyan. 488 nm is cyan. 492+ nm would be closer to teal but could be argued to be a cyan green.

 

[Gazen]

So, since these diodes tend to vary per individual diode. Does anybody know if Sanwu actually tests them? Or do they just use one of these diodes and label it 488nm?

I'm just curious if it's possible that their "492nm @ 100mW" and their "488nm at 55mW" is tested anyways.

So let's say, is it possible to order the "492nm @ 100mW and end up with a diode that's putting out closer to 488. Or vice versa?

They spectroed all of the first lasers they sent out and labeled their wavelength, so I’d assume that they are still doing that. They’ll probably make sure it’s 488 if you email them beforehand.

 

[hxdrummerxc]

They spectroed all of the first lasers they sent out and labeled their wavelength, so I’d assume that they are still doing that. They’ll probably make sure it’s 488 if you email them beforehand.

Ok thanks, I'll try and email them


Another question for you all,

They offer two different lenses. G2 and G7. It says that the G7 is recommended, but that's a generic note for all their wavelengths. Which lens produces better results on these sharp diodes?