Why don't we make laser pointers backwards?

[Addonex]

I was just thinking about frequent problems that I've seen in laser pointers like the "wings" from diodes or splash, I'm no expert on optics but wouldn't it be beneficial to build a laser the other way around?

By using the entire body length of the pointer for optics with a narrow aperture at the very end I would think that much better beam characteristics would be achievable, as well as eliminating the unwanted bits since they have a chance to diverge away from the dot. Here's an example of what I was thinking:

Would be interested to hear from someone more knowledgeable about this

 

[Wolfman29]

Think of how difficult that would be to make

 

[ARG]

Interesting! I like the idea. I think the best way to use this room would be to use a 405-G-2 to colimate the beam then use cylindrical optics to correct it. That would probably give you the best beam specs for a multi-mode diode. Prisms might give you even better results, but those are a pain to setup for a handheld.

However, I hate beams that do not come out of the laser centered and this would drive me insane

But to answer your question, the reason lasers aren't made backwards like this is because most lasers are built from flashlights and the reflector is replaced with the heat sink, doing something like this would cost a lot more as it requires a custom host.

 

[InfinitusEquitas]

I was just thinking about frequent problems that I've seen in laser pointers like the "wings" from diodes or splash, I'm no expert on optics but wouldn't it be beneficial to build a laser the other way around?

By using the entire body length of the pointer for optics with a narrow aperture at the very end I would think that much better beam characteristics would be achievable, as well as eliminating the unwanted bits since they have a chance to diverge away from the dot. Here's an example of what I was thinking:

Would be interested to hear from someone more knowledgeable about this

That is a very interesting approach. The same approach has been done in projectors, but I don't think in any handhelds.

 

[Addonex]

Interesting! I like the idea. I think the best way to use this room would be to use a 405-G-2 to colimate the beam then use cylindrical optics to correct it. That would probably give you the best beam specs for a multi-mode diode. Prisms might give you even better results, but those are a pain to setup for a handheld.

However, I hate beams that do not come out of the laser centered and this would drive me insane

But to answer your question, the reason lasers aren't made backwards like this is because most lasers are built from flashlights and the reflector is replaced with the heat sink, doing something like this would cost a lot more as it requires a custom host.

I agree that it's not very simple compared to a flashlight host, though I was thinking along the lines of fully custom machined hosts. If you're already making it from scratch, it wouldn't be much more difficult to make one this way if you're trying to attain a really nice beam. I'm just unsure how it would actually function in that kind of scale

 

[Blord]

The laser need adjustment screws in 2 directions. And the laser will also be non-focusable unless you find a genius solution for it.

 

[Things]

Also, what's the point really? If you want awesome beam specs, look at a lab laser, that's what they're designed for.

It's a cool idea, it's just that beam profiles in a handheld don't really matter.

 

[ped]

As has already been said, great idea!

If the beam was collimated to ∞ at the diode end , you should be able to focus it at the aperture no? the problem is you'd need a bigger host to accommodate the lens assy and battery alongside.

 

[InfinitusEquitas]

Also, what's the point really? If you want awesome beam specs, look at a lab laser, that's what they're designed for.

It's a cool idea, it's just that beam profiles in a handheld don't really matter.

Having the lens in front of the laser, detracts from the beam significantly, even in handhelds.

I often use a piece of pipe so when the beam exits there it's much more of a contrast. You can try it with any tube... even the cardboard from inside a paper towel rolls (I did that until one accident where it kind of caught on fire).

Same principle as with a black beamstop absorbing the light, so you can appreciate the beam more.

Personally I don't have the skills for it, but the design really doesn't require all that much work... one cavity on top of another. Could even we done with two flashlights... One on top for the laser diode and heatsink, the other on the bottom/side to hold batteries.

 

[ZRaffleticket]

I was looking up some host ideas today; actually this was one of the things I came across (but not in this thread). Flashlights are made like this. The only difficult thing is finding the right host. I'll try to find that flashlight again...

 

[lowell389]

That is interesting for sure. It could be made of some turnable urethane prototyping material , to keep it cheap until the bugs were worked out of it. Such as where the different points of opening would be for placing of the lenses , and driver. With your ok , and if I get enough spare time. I'd like to play around with the idea. If I can make one that looks like it would work , I'll send it to ya to try your idea out . I don't have any of the laser bits to compleat one.

 

[InfinitusEquitas]

Another thought occurred to me... this design approach could work to incorporate a beam expander into the laser.

It's definitely promising, and would be nice to see something that isn't square or round for once.

 

[JLSE]

An interesting idea, but not entirely necessary.. You could just lengthen
the front a bit and use spatial filtering.

As pictured above, you would need to use both a mill and lathe to make that host
so for most, it would be a task and a half.

With spatial filtering, you could use any center line host, and just work the magic
on the head and heatsink dimensions :beer:

 

[Wolfman29]

That seems so obvious now