Ok, so please tell me if I have this right...

I've been researching the forum for awhile, and information has been rather hard to come by. I'm about to build a red pointer, and I've been after the tightest, least divergent setup that I can find. It seems to me that the Meridith glass lens module is the one that will suit the bill for me, with the lowest divergence and tightest beam? Well, out of the regularly available options anyway.

The vast majority of information that I've been able to find on this subject has focused on burning and focusing ability, and these things don't really concern me. I've done my homework, do I pass the test? lol

you could always get a red module with good divergence and replace the driver/diode.

Yeah.... you've done your homework....


Jerry

I've had a lot of luck getting a tight clean beam using the Aixiz glass lenses.. I've never used meredith glass before, so I can't speak from experience, but I have heard very good things..

quadcam;

This is another lens AR coated specifically for RED, that I think will compare favorably:
http://laserpointerforums.com/f50/new-hi-power-lens-red-lasers-41632.html

It mounts in the machined brass lens housing with tighter threads.

It is a shorter FL than the Meridith.

LarryDFW

LarryDFW said:

quadcam;

This is another lens AR coated specifically for RED, that I think will compare favorably:
http://laserpointerforums.com/f50/new-hi-power-lens-red-lasers-41632.html

It mounts in the machined brass lens housing with tighter threads.

It is a shorter FL than the Meridith.

LarryDFW

Click to expand...

Shorter focal length... does that mean it will collimate better or worse than the Meridith? What exactly does that mean?

Shorter FL usually means narrower beam diameter at aperture, higher divergence overall.

Meredith is about 5% more power for red than the lens that Larry and I sell for blu-ray.

Although the 405-G-1 glass lens is a good lens for red as well!

Shorter focal length, also means that the lens is closer to the diode at focus. It means that the focusing will be a little 'touchier' as well.

More about Meredith...

They are switching to their broadband lens that is good for both red and blu-ray. It is not as good for red as their 'optimized for red' lens that they are discontinuing. But it is a very good lens.

I have a few of the 'best for red' Meredith's left that I modify for an AixiZ fit:
http://laserpointerforums.com/laser_pointer_forums_3/forum/showthread.php?t=22501

Take look at this thread that shows power comparisons for red and blu-ray using several different lenses:
http://laserpointerforums.com/laser_pointer_forums_3/forum/showthread.php?t=33965

When comparing power to the popular AixiZ acrylic, it is important to note whether the back plastic is cut off of the AixiZ acrylic lens or not. The readings will differ depending on that.

This is why Larry gets a higher power difference, his comparisons are with an 'AixiZ New Plastic Lens'. (back not open)

I make all of my comparisons with the AixiZ acrylic 'back opened', because most people cut the black plastic away on AixiZ acrylics. If you don't, the plastic will start to melt...
Jay

You can use a beam expander which is just what the unit is from Meredith.
like this unit from Lasermate Laser Accessories- Optics
TC-10X. Your divergence will be based upon your diodes beam diameter.
This unit cost me $50 plus shipping when I bought it a year ago.

The Meredith lenses I am referring to are not three element assemblies...

They are their high quality single element Aspheric lenses shown here:
Meredith Instruments
Jay

steve001 said:

You can use a beam expander which is just what the unit is from Meredith.
like this unit from Lasermate Laser Accessories- Optics
TC-10X. Your divergence will be based upon your diodes beam diameter.
This unit cost me $50 plus shipping when I bought it a year ago.

Click to expand...

Hi steve,

did you used tx-10x expander with aixiz modules or is working just with meredith?

did you measured tc-10x transmittance? I am just courious about how much power you will loose just to cross the expander. More than 20%?

Also, I saw is coated but I cannot see for what wavelength? Do you have an idea?

Regards,
Alx

^ Just a little trick, that works 90% of the times

Look the reflex of a broadband light source (sun, an incandescent lamp, so on) on the surface of the lens that you want to see what coating is, and, basically, the color for which the lens is coated, is almost all the times the complementar (or opposite, if you prefer) of the color that you see in the reflex (not all the times, and not for multicoating, but for single wavelenght AR coating is almost all the times valid)

This cause the coating must left pass the more possible part of the interested wavelenght ..... as example, lenses for red and IR, are usually blue or green, lenses for BR looks amber or orange, lenses for green looks like violet (when they don't use broadband coatings) and so on .....

The only problem can be with multicoating broadband, that being made for almost all the visible spectrum, looks just a very faint reflection without a specific color dominant, and sometimes changes a bit the color changing the reflection angle.

The only other way for know this, is made a DIY absorption meter for lenses ..... is not complex, but you need to find at least 5 very small photodiodes, two of them must work one in IR and one in UV, the others in visible spectrum.