At first I thought M4D M4X was talking to me as I saw his post right after mine. I thought WTH? Then I saw the “Zeng@LM” crap. Typical posting you see on the laser forums, too. You’re talking about something in a thread, like a blue laser diode, and the typical “Zeng Lee Foo” pops in with links to some random chaotic crap saying, “try this, try this, it’s flashlight!”
…IT’S SO, |)@NM, ANNOYING.
Eh. Anyways. I have a sample coming in the mail from them of the new coating, I don’t have any official pricing yet until received. Usually with broadband AR coatings, you might have to give up a little % loss at one wavelength region or another when dealing with white light, since you have 3 color regions spanning the output. So a choice might have to be made. With this stuff, it’s just a flat-line across the visible spectrum (based on the line graph). Exactly what you want to see. I’m hoping tests confirm this once it arrives. Usually blue light at lower wavelengths is the color area where the coating falls off in transmittance a little. So you get a very deep/royal blue reflection from the lens back at you from white light that will be dimmer the better. The red that reflects out is closer to the IR range (where the broadbands usually fall off in transmittance value), which your eyes don’t pick up so well—leaves the blue as all you see. Some coatings fall off further in on each end of the visible spectrum which they can pass, resulting in a pinkish-purple color, like in below photo. Regardless of how colorful it looks, it sure helps ANY lens get a greater total amount of photons through.
The way I have found the acrylic lenses, is by measuring the OD with a caliper when I find one in a light. They might be 38.25mm on average for a given light, so I search for a “38mm” plastic/acrylic lens, find one with detailed pictures, hold the lens I have in hand up in front of the PC monitor until the scale outline syncs with the photo on-screen, see that they both have the same mold pattern of (3-4) dots on the rim with same exact curvature, and voila. A match. This is just how I have tracked down matches to lenses already found in a light, so I can confirm a source. Then that seller might link to a list of acrylic sizes they carry, and you can assume they’re likely all alright for acrylic. But if I can get the lens from Edmund/Thor in the size and FL I need, it’s probably better (these companies work harder on lens patterns they produce to get them right, which is reflected in their prices). It’s just up to you if you want to pay $40+ per “good” lens and gamble on it working for you. The problem is, I don’t know of too many larger acrylic lenses out there. Those are usually <50mm, then become scarce in any real selection past that diameter.
Big lights just let me use big lens sizes that don’t have to be within a mm or two to work. Turn some spacers and hold a slightly smaller lens if needed.
When I get some extra time I’ll apply some of my tricks to a 140X light and see what can be done. I have a couple other aspheric lights in line on the bench which I want to finish first, but definitely will grab one of these with a chunk of copper bar.
Some AR coated optics and one of my apertures—might help a 1405. For S&Gs…
1/16000 ISO 100 right inside the reflective aperture @ 4A. Dome still on (aperture-testing LED).