Green laser lost focus
-
loneoceans
- Posts: 15
- Joined: Mon Nov 05, 2007 1:07 pm
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Greetings,
With regards to the green laser losing focus, I assume you all mean that the divergence has increased (i.e. the dot gets bigger when you point it at something?). This probably means that the optics have gone out of collimation, and you just need to focus the primary lens that focuses the laser.
Nobody has made a green laser diode yet (at least not cheaply), so all green 532nm lasers begin life with a 808nm IR laser diode, which is pumped through a Nd:YVO4 (Vanadate) crystal to convert the wavelength to 1064nm IR, then through another KTiOPO4 (KTP) frequency doubler crystal to give you the lovely green light. There usually is an IR blocker also to block out all residual IR light.
A laser diode is very small and does not exhibit good collimation (that is the beam actually comes out with a huge divergence (this depends on the diode and those which i've worked with diverge about 20 degrees or so out of the diode).
After all that pumping through the crystals, there is a lens at the front which focuses the laser to a nice parallel beam which we all love. I'm not sure about all your lasers but you could possibly open up them and observe the front of the laser. There might be a lens attached to a threaded adapter at the front. By carefully twisting the lens (hence bringing it in or out depending on which way it went out of focus), you will be able to bring it back to focus.
For some models there is a little screw groove on the threaded ring which holds the lens so that'll be easy for you to just find a suitable screwdriver to adjust
Of course your green laser might not be as easy to adjust as some other lasers which I have seen. It depends on the manufacturer I guess.
Finally: http://www.kellerstudio.de/repairfaq/sam/grnorg1.jpg
This photo shows the various parts of a green laser!
Hope this helps. =)
With regards to the green laser losing focus, I assume you all mean that the divergence has increased (i.e. the dot gets bigger when you point it at something?). This probably means that the optics have gone out of collimation, and you just need to focus the primary lens that focuses the laser.
Nobody has made a green laser diode yet (at least not cheaply), so all green 532nm lasers begin life with a 808nm IR laser diode, which is pumped through a Nd:YVO4 (Vanadate) crystal to convert the wavelength to 1064nm IR, then through another KTiOPO4 (KTP) frequency doubler crystal to give you the lovely green light. There usually is an IR blocker also to block out all residual IR light.
A laser diode is very small and does not exhibit good collimation (that is the beam actually comes out with a huge divergence (this depends on the diode and those which i've worked with diverge about 20 degrees or so out of the diode).
After all that pumping through the crystals, there is a lens at the front which focuses the laser to a nice parallel beam which we all love. I'm not sure about all your lasers but you could possibly open up them and observe the front of the laser. There might be a lens attached to a threaded adapter at the front. By carefully twisting the lens (hence bringing it in or out depending on which way it went out of focus), you will be able to bring it back to focus.
For some models there is a little screw groove on the threaded ring which holds the lens so that'll be easy for you to just find a suitable screwdriver to adjust
Of course your green laser might not be as easy to adjust as some other lasers which I have seen. It depends on the manufacturer I guess.
Finally: http://www.kellerstudio.de/repairfaq/sam/grnorg1.jpg
This photo shows the various parts of a green laser!
Hope this helps. =)