Should I get a G1 Glass lens for my SL-R?

[JBTexas]

I've PM'd Garoq, awaiting news, but I may as well ask for as many opinions as I can get.

Should I order a G1 glass lens for my Survival Laser 660nm 300mw? (which I ordered with the default AR coated acrylic lens).

I've already searched through the forum, re: "Glass versus Acrylic".

Didn't help as much as you might expect.

Two (sometimes three) consistancies:
(a) Glass is generally easier to clean without damaging the lens than acrylic.
(b) Glass is less prone to damage than acrylic.
(c) GENERALLY it is said "glass = more performance".

Burning is fine, but my priority is visibility-over-distance. *IF* a G1 results in *significant* output improvement over acrylic, that amounts to the same thing; more output = more visible; DISREGARDING a difference of divergence.

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About the acrylic that I DO have... I have some artifacting, and I don't know if this is normal. Maybe it IS normal for acrylic, but would NOT show up w/ a glass lens.

Unfortunately I do not have a digital camera.

The SPOT is just fine. The laser burns. The laser can focus and can focus a bright spot a very far distance away.

There IS a weird little thin red line going through the spot extending outwards, when focused to a good / perfect spot. Searching the forum indicates that is normal, and some people even find it useful for attaining good focus.

(1) A (dimmish) red halo around the bright spot containing what looks like "mottled alligator skin". Like a diffuse halo of dim red light shining through "transparent slightly melted plastic".

(2) When set to a soft focus, where the spot is at least > 4 inches or so, I see some... "ripples"... off of the center of the spot... it looks almost like a partial fingerprint, or a piece of a fingerprint. NO, when assembling the laser I did NOT at any time touch the lens. I call it a fingerprint... I don't know... it could be just some optical effect, a minor imperfection, something that some acrylics are just going to have.
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I've already spent quite a bit of money this month. I can / am willing to spend more, *IF* getting this glass lens = a benefit(s).

- Thanks

EDIT: Oops I forgot to reference this:
http://laserpointerforums.com/f50/weird-dust-around-dot-64389.html

I found that thread while searching for possible answers on those artifacts, which may or may not be associated with simply having an acrylic lens.

No, the lens not get stained with soot.

I tried cleaning both sides of the lens w/ a *DRY* lint-free Q-Tip, NO LIQUIDS, and then I used a can of compressed air.

No change.

Under a magnifying glass, the little acrylic LOOKS fine.

 

[LaZeRz]

The artifacting is just because of light reflections inside the lens/module (I think)

The g1 lens will still give you some artifacting but it will also give you around 25% more power then a acrylic or aixiz glass (I cant remember)

Most red lasers have that line going thru the dot.

 

[JBTexas]

Yes - that is one reason why I am tempted to switch to the G1. Opinions seem to vary on how much MORE light transmission there would be with a red, though.

... good to hear that I am not the only one seeing those artifacts.

 

[Johnyz]

If you want beam quality, get the Aixiz three element instead. They give less mW's than 405-G-1 (but more than acrylic), but due to them being 3 element, they shape the beam/dot better. Of course, the best bet would be getting specialized correction prisms if you wanted perfect dot.

 

[daguin]

If you want beam quality, get the Aixiz three element instead. They give less mW's than 405-G-1 (but more than acrylic), but due to them being 3 element, they shape the beam/dot better. Of course, the best bet would be getting specialized correction prisms if you wanted perfect dot.

He's talking about a 660nm RED laser :can:

Peace,
dave

 

[yzer]

Before moving up from an acrylic lens for red to a $50 single element design I'd recommend trying the AixiZ 3-element AR multi-coated glass 635nm-670nm lens. At $5.00 you can't go wrong by trying it. I'm getting a nice long-throw beam at 240mW 660nm with it.

AixiZ Red Laser Glass Lens 635-670nm, AixiZ

 

[Johnyz]

Darn, I saw Survival Laser and immediately thought 445.. Anyway, like yzer said, still 3 element, but coated for red. qumefox also sells acrylic coated for red for $3.50.

 

[JBTexas]

yzer;

Thank you VERY much; that is what I am looking for; "I actually did this and it works". Very important to a total newbie like me.

I cross-referenced that item w/ Survival Lasers to make sure that it would fit (right size etc., heck, what do I know?); apparantly it will.

The AixiZ website is apparantly operating under a "Texas License"; if he ships from Texas I imagine that I will get it pretty soon. (The location of AixiZ isn't specifically stated on the site).

I will order 1 in a few minutes (and look at what else is there).

 

[RA_pierce]

I vote for the G-1 lens.
The three element Aixiz glass lenses are alright, but the beam is very wide and not very gaussian.
With the G-1 lens you will get more power, obviously, AND a thinner beam, AND a more gaussian profile. That is, the power density is higher in the center of the beam.
And as an added bonus, the divergence with the G-1 lens is comparable to what you get with the Aixiz lens. The difference is so small you won't notice it.

The only laser diode the short focal length aspheric lenses are not good for are multi-mode diodes like the single emitter 445s and multi-emitter red and IR diodes.

In my opinion, they are the best lenses for violet and red lasers - no contest.
Any artifacts that you get with the G-1 lens are not from internal reflections and wasted power like the 3-element glass lenses, but from the laser diode itself. The G-1 has a larger aperture so captures more light including some of the extra emissions.
In my experience, the LOC and LCC diodes do not produce a lot of splash (not as much as 405nm diodes) so you will still get a clean beam.

With the G-1 lens you should be able to do burning tricks with >300mW without focusing.
If you want the best power and the best beam from your red laser, get the G-1 and don't settle for the Aixiz 3-element lens.

I know it reads like a sales pitch, but seriously... After using the G-1 lens for 405 and 650, I will never go back to the Aixiz lenses.

 

[JBTexas]

Oh well. AixiZ website is malfunctioning, will not let me log on, will not let me shop; I clicked "forgot password", got the email with the new ISSUED password, tried that one, tried the old one... screwit. I invoked "Contact Us" on the website. Maybe I will hear from him. I've had a few frustrations this week, they are starting to mount up.
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RA_pierce; I have a concern about the G-1 on the Survival Laser website; if you look it up under "Laser Parts and Assemblies"; it is $99.50; states :

... and can boost the output of your 405nm & 445nm lasers by 10-15% or more! Best for when you want the absolute maximum power and brightness for burning and close-up work. Note: The G-1 lens provides somewhat higher beam divergence due to the single-element design, and the laser "spot" will not be as "clean" as with the standard 3-element lens. In addition, this lens will not work with the SL-LS1 external lens spring because the lens must be threaded nearly all the way into the diode module for proper focus. Use teflon tape to adjust the fit in the module instead. For more information on the G-1 lens element, click here to download the G-1 lens data sheet.

The data sheet states: "Design Wavelength (λ): 408nm".

If you order one of the two SL-R 660nm red laser bundles, there is a "Red Lens Option" in a dropdown box : "G-1 High Efficiency (add $89.50)"

I PM'd Garoq, awaiting info, I asked if those are both the same lenses, or if his company has a *RED* G-1, but only sold as part of the red laser bundle.

The rest of your input; thanks, it's appreciated. I PM'd Garoq with a LOT of questions (incl. the one above). I'll get this sorted out. All I am waiting for, I think, is verification as to whether there is a "RED" G1 at survival laser.

If the AixiZ website was working, I would say to myself "get both lenses and try them, that is how you get experience", and the AixiZ lens is $5.00. We'll see.
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He has already told me, previously, that I would have the same problem with the G1 as with the standard red acrylic that I have... when focused to infinity, there is no room for a lense spring, and I will have to use teflon tape. I have never used teflon tape, I am new to all of this. I am disabled, my heart meds prevent me from driving, and I can't "run out to the local hardware store", I ordered teflon tape online, it is supposed to get here in 1-2 weeks.

I did take the laser outside last night, and focused to infinity (target was a building 250 meters away); yes; when focused to infinity, there is ONLY a 2mm clearance between the lens focusing ring and the heat sink.

FORTUNATELY, when changing focus towards a burning point (closer), the lens gets screwed "outwards"; so the problem will never be worse than 2mm.

I wish there was an alternative, but I have asked, checked, searched... it rankles that I would have to wrap the threads in tape, and then have to scrape off the old tape occasionally and put on new tape, and watch out for tape-bits falling into the diode. Seems kind of "Fred Flintstone". And the laser is an expensive item that might be some day destroyed by ... "tape".

 

[InfinitusEquitas]

@JBTexas

If burning is not a priority to you, why not adjust the laser to infinite focus and leave it that way?

If you have a spare spring you can also try cutting it in half, and using a smaller piece just for some tension... did that on one of my lasers, works well enough.

Considering the clearance amount, a tiny o-ring could also do the job... did that with a laser I just got the other day and it works perfectly. I can't focus the laser for burning, but it holds focus well enough so that I don't have to readjust every time I want to use it.

As far as the lenses go... I've read, and heard from a lot of people that aixiz is better for the beam/visibility. Less power, but if you're not gonna use the laser for burning.. who cares.

 

[RA_pierce]

Ah, I see.
I was not aware that SL sold the G-1 lenses.
One of our members here, Jayrob, was one of the first to begin offering these lenses. Check this thread:
http://laserpointerforums.com/f64/fs-405-g-1-glass-lens-mod-31-increase-vs-aixiz-22497.html

The coating being specified for 408nm must refer to the 405-G-1. Jayrob also sells the 650-G-1 lens for red lasers. The 405-G-1 and 650-G-1 both work well for red lasers, but the 650-G-1 lens does not work for violet lasers.

The note about the higher divergence on the SL website is probably referring to the 445s, which, because of their beam profile, do not work well with this lens. However, they are great for single mode diodes like your red laser. The "slightly higher divergence" is very slight.

@InfinitusEquitas:
What you have heard about the Aixiz being better for beam quality/visiblity is not generally true.
If anything, the G-1 lenses will always produce a brighter beam, since they pass more light. Also, the beam diameter with the Aixiz lenses is a couple millimeters wider meaning the beam is less dense, so dimmer up close.
The 3 element lenses do give a tighter bar with the 445nm lasers, but only because the focal length is longer, and the lens cuts off a good portion of the output.

The G-1 lenses are also not just for burning power.
The beam out of one is much thinner and brighter. The reason I like the G-1 lenses is that I mostly build pen style lasers. With limited mass for heat-sinking, it is important to get the most light out with less work being done. A high transmission lens means you don't have to run your laser as hard for high output power and less heat is produced.

I'll say it again... My opinion is that in our hobby there is no available lens that is all around as good as the G-1 lenses for single-mode diode lasers.
For multi-mode diode lasers, both the G-1 lenses and the Aixiz lenses suck without beam shaping optics.

Oh yeah... The teflon tape is not that bad. If you can get some, use it. I like it better than the spring. The spring sometimes scrapes off metal from the lens nut. I've never had a problem with tape shreds getting on my lens. Also, I don't need to change it more than once a couple months.

 

[JBTexas]

@ InfinitusEquitas

Actually when focused at infinity, I managed to burn a hole in a brown plastic trash bag across the room.
I just had to hold the laser VERY still, resting on my knee.

2mm is NOT very much clearance. Even with a *piece* of a spring, it would only impose a LITTLE tension (probably not enough to matter) at about the infinity focus point . And of course, focusing past that (outwards) the ... "spring will run out of sprung" pretty quick. I used bits of various copper wires as an "exploration of concept". Some kind of spring out of something like an old watch MIGHT work, IF it was strong enough. But I dont' have an old watch.

I DID think of using an O-Ring. Can't get out to the hardware store. BUT I have "scrap stuff". One good thing; this laser apparantly has a HIGH duty cycle (stated: continuous); after minutes the end of the housing "gets warm"; by now I can judge how hot it gets. A little cylinder shaped piece of foam is probably not wise, but I have other stuff I am trying. At least, that way, AT infinity focus, the lens won't be jumping around; if it is disengaged from "Mister Squishy Cylinder" for burning, who cares, the lens can jump a bit.

There is something else I *like* to do with this Survival Red and my Gatlin... I guess you could say "the opposite of a burning demonstration"; I defocus to a large spot (say, > 2-3 inches) and it makes my radiometer spin like a whirlwind. I'm afraid a hard focus would damage the radiometer.

SO, if possible I would like the OPTION of being able to change focus. We'll see, I'm still messing around w/ the "compressed cylinder of squishy stuff idea" (basically a homemade o-ring). Just haven't found the RIGHT stuff yet from "The Magic Closet" (that cave off of my bedroom where I keep less-often-used ham radio stuff, old books, stuff that hasn't been unpacked in 15 years... that kind of thing).

 

[JBTexas]

RA_Pierce;

Noted, thanks... there was stuff in the thread that is over my head and it isn't clear precisely what *I* would have to do (versus what jayrob provides). I'll wait and see what garoq has to say, re: more info on his G1 (or G1's, *IF* he has 2 versions).

 

[JBTexas]

Loose focus = fixed!

I don't know many of my neighbors... I'm not that sociable, and I want to ... umm... diskumbobulate ... my upstairs neighbors... but there are a couple that I get along with. I just happened to ask one, and he HAPPENED to have some o-rings!

Found a size that works perfectly... (approximately, by manual measurement) 12mm in diameter (+/- 1-2mm), and looks EXACTLY 3mm thick. SO for the benefit of Survival Laser owners or people using C6 hosts...

He gave me the 3 of that size that he had, and gave me 3 more of varied smaller/larger sizes in case a similar situation/different laser occurs. (this old guy gave me his ENTIRE o-ring collection... hehehe). He's a retired "oil-guy" dunno, used to fix oil wells or something.

Holds the lens tight (PERFECT tension) at infinity (too bright right now to hit my 250 meter target, but I have a closer building I can use... I can "just tell" - can get to a bright small spot and focus well past that point...)... AND can hold tension through burning distances. This acrylic lens is touchy that way - don't have to move it much. I have to disengage the bottom of the focus ring from from the o-ring a little to shoot my radiometer.

Garoq hasn't replied yet on the G1. Could be out vacationing for the weekend or something.

 

[InfinitusEquitas]

Glad to hear O-ring worked

Garoq's probably out partying... I'm going out in a bit too I predict: :beer:op::friend::gh::drunk: and for some people :barf:

Kind of wish we had more smileys on this forum.