Krutz
0
- Joined
- Nov 21, 2007
- Messages
- 1,733
- Points
- 48
hello everyone,
i plan to build a matched set of red, green and violet pointers. the green bare module (o-like) is too long. so i try to shorten it by changing the optics. i removed the frontal collimating lens, with replacing it with a shorter focusing one i could gain a few mm. not enough..
i removed the widening lens directly on the kpt chip, so now i have the bare lasing crystal without any optics afterwards. the beam is surprisingly good! at the crystal, its a fraction of a mm, perhaps a tenth. after two meters, its "only" a few cm, perhaps two (or one inch). round and with no spill. so far nothing unexpected..
i tried to collimate the beam with a single lens. no matter what i try, the dot gets much larger than without anything. a 0.8mm short-focus lens (objective lens from a sled), a medium-length focus aixiz lens, a long-focus (several cm) telescope lens, they all dont focus at all but widen the dot after two meters to ten or more cm. no matter how close or far i put the lens (unprecisely with my fingers).
i would have thought that i simply put a lens at its focal length to the chip (or, worst case, at the distance to the back end of the chip), and voila, whatever the size of the beam hitting the lens is, will be a somewhat collimated beam? just like with regular diodes? i dont get it!
the module with the lenses removed is less than 2 cm (1 inch), so a lens a few mm away from it would really shorten it! originally its more than twice that length!
any ideas? any way to collimate it with a single element?
or is there a reason why they use two elements.. *smile*
manuel
i plan to build a matched set of red, green and violet pointers. the green bare module (o-like) is too long. so i try to shorten it by changing the optics. i removed the frontal collimating lens, with replacing it with a shorter focusing one i could gain a few mm. not enough..
i removed the widening lens directly on the kpt chip, so now i have the bare lasing crystal without any optics afterwards. the beam is surprisingly good! at the crystal, its a fraction of a mm, perhaps a tenth. after two meters, its "only" a few cm, perhaps two (or one inch). round and with no spill. so far nothing unexpected..
i tried to collimate the beam with a single lens. no matter what i try, the dot gets much larger than without anything. a 0.8mm short-focus lens (objective lens from a sled), a medium-length focus aixiz lens, a long-focus (several cm) telescope lens, they all dont focus at all but widen the dot after two meters to ten or more cm. no matter how close or far i put the lens (unprecisely with my fingers).
i would have thought that i simply put a lens at its focal length to the chip (or, worst case, at the distance to the back end of the chip), and voila, whatever the size of the beam hitting the lens is, will be a somewhat collimated beam? just like with regular diodes? i dont get it!
the module with the lenses removed is less than 2 cm (1 inch), so a lens a few mm away from it would really shorten it! originally its more than twice that length!
any ideas? any way to collimate it with a single element?
or is there a reason why they use two elements.. *smile*
manuel
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