Achieving a smaller beam diameter with 803T optics

[Jimmymcjimthejim]

Re: Achieving a smaller beam diameter with 803T op

Would this reduce power?  Is the opening getting smaller, or just a better lense?

Power is not reduced with the new lens. The lens has a much shorter focal length, making it more effective at shorter distances. The shorter the distance, the thinner the beam. Actually, I think that this will increase the power compared to an AixiZ acrylic because these lenses look like they are AR coated.

 

[LiveRock]

Re: Achieving a smaller beam diameter with 803T op

This is very interesting.... I'll try it as soon as I have some free time...

if this proof to be so good, we may do as standard in future... when we order from from GB, we may request this procedure as standard;

1. Harvest the diode from sled
2. Harvest the lens from sled
3. Remove lens from Axiz module and replace with sled lens and place diode

 

[Bionic-Badger]

Re: Achieving a smaller beam diameter with 803T op

Hmm, I tried this out without much success, but I was trying the lens from the KES-400A. That sled has two lenses in the aperture, rather than one. The first one is a spherical lens, and the second is, I believe, a Fresnel lens, the one with the concentric circles. I was seeing if I could use just the spherical lens to create a sharp beam without any of those circles. However, I wasn't able to get it to focus. It seemed like the focal point was behind the laser, so it'd always diverge. Someone else ought to try it out and see.

One question though, to Jimmymcjimthejim or whomever: did you cut the back of the lens nut to allow more light into the lens? I want to know if the beam is still nice and small after doing that. Also, from the PHR-803T lens I also tried: one side appears to be reflection-coated, and for a violet color, probably to keep back-reflections from entering the sled. This was on the flat side. Was the flat side of the lens facing the laser? I wasn't sure from the desciption. If so, it might reduce the power of the laser, while also sending energy back into the diode.

 

[Jimmymcjimthejim]

Re: Achieving a smaller beam diameter with 803T op

Hmm, I tried this out without much success, but I was trying the lens from the KES-400A.  That sled has two lenses in the aperture, rather than one.  The first one is a spherical lens, and the second is, I believe, a Fresnel lens, the one with the concentric circles.  I was seeing if I could use just the spherical lens to create a sharp beam without any of those circles.  However, I wasn't able to get it to focus.  It seemed like the focal point was behind the laser, so it'd always diverge.  Someone else ought to try it out and see.

One question though, to Jimmymcjimthejim or whomever:  did you cut the back of the lens nut to allow more light into the lens?  I want to know if the beam is still nice and small after doing that.  Also, from the PHR-803T lens I also tried:  one side appears to be reflection-coated, and for a violet color, probably to keep back-reflections from entering the sled.  This was on the flat side.  Was the flat side of the lens facing the laser?  I wasn't sure from the desciption.  If so, it might reduce the power of the laser, while also sending energy back into the diode.

The back of the lens nut (that holds the lens in this case) does not need to be cut out. I did notice, though, that if you do cut it out, then you just get more scatter around the beam. The round side is facing the laser. I tried it with the flat side facing the laser, and the lens has to be so close to the diode, and it doesn't work that well.

 

[Krutz]

Re: Achieving a smaller beam diameter with 803T op

thats the point!
bluray and hd-dvd have a lens-media distance of under one millimeter, which therefore is the focallength of the lens. the lens is a regular lens (aspheric i am sure) with a fresnel-like ringstructure on one side. so if you use the flat side and move it to its focallength to the diode, it should make a nice tiny dot, and perhaps even without distortion. that depends on the angle of the diode (without lens), if its narrow, it will only light through the middle, good part of the lens. either way, you can just cover the bad outer part with the lens nut, or paint, or alu-foil.
for some info about those lenses (there its the KES one):

http://www.fineartradiography.com/hobbies/lasers/blu-ray/optics.html

Objective (disk read) lens with voice-coil focus and tracking servos. This lens is very special and comprises of a zone plate (diffractive element) below a very high numerical aperture objective with a very unique shape.

i did some experiments with lenses too.
some time ago, when i tried, i got those rings as well, and forgot about those objective lenses. now again on it, no rings, a clear spot, and narrow beam! was a 16x dvd burner lens, not even glued in very accurately. if you tilt/off-center the lens just a tiny bit, you get the strangest patterns, without being easily able to tell into what direction to correct, and possibly having the impression that there is no "good spot" at all. try again

i didnt try kes or phr lenses yet, but these are what i have in mind for my next bluray

i will report back!

manuel

 

[Jimmymcjimthejim]

Re: Achieving a smaller beam diameter with 803T op

thats the point!
bluray and hd-dvd have a lens-media distance of under one millimeter, which therefore is the focallength of the lens. the lens is a regular lens (aspheric i am sure) with a fresnel-like ringstructure on one side. so if you use the flat side and move it to its focallength to the diode, it should make a nice tiny dot, and perhaps even without distortion. that depends on the angle of the diode (without lens), if its narrow, it will only light through the middle, good part of the lens. either way, you can just cover the bad outer part with the lens nut, or paint, or alu-foil.
for some info about those lenses (there its the KES one):

http://www.fineartradiography.com/hobbies/lasers/blu-ray/optics.html

Objective (disk read) lens with voice-coil focus and tracking servos. This lens is very special and comprises of a zone plate (diffractive element) below a very high numerical aperture objective with a very unique shape.

i did some experiments with lenses too.
some time ago, when i tried, i got those rings as well, and forgot about those objective lenses. now again on it, no rings, a clear spot, and narrow beam! was a 16x dvd burner lens, not even glued in very accurately. if you tilt/off-center the lens just a tiny bit, you get the strangest patterns, without being easily able to tell into what direction to correct, and possibly having the impression that there is no "good spot" at all. try again

i didnt try kes or phr lenses yet, but these are what i have in mind for my next bluray

i will report back!

manuel

Ok! Let me know what happens.

And with the PHR spherical lens, if you put it the other way, then it has to be so close to the diode that the spring barely fits.

 

[Spyderz20x6]

Re: Achieving a smaller beam diameter with 803T op

[quote author=Krutz link=1225571544/20#20 date=1227026467]thats the point!
bluray and hd-dvd have a lens-media distance of under one millimeter, which therefore is the focallength of the lens. the lens is a regular lens (aspheric i am sure) with a fresnel-like ringstructure on one side. so if you use the flat side and move it to its focallength to the diode, it should make a nice tiny dot, and perhaps even without distortion. that depends on the angle of the diode (without lens), if its narrow, it will only light through the middle, good part of the lens. either way, you can just cover the bad outer part with the lens nut, or paint, or alu-foil.
for some info about those lenses (there its the KES one):

http://www.fineartradiography.com/hobbies/lasers/blu-ray/optics.html

Objective (disk read) lens with voice-coil focus and tracking servos. This lens is very special and comprises of a zone plate (diffractive element) below a very high numerical aperture objective with a very unique shape.

i did some experiments with lenses too.
some time ago, when i tried, i got those rings as well, and forgot about those objective lenses. now again on it, no rings, a clear spot, and narrow beam! was a 16x dvd burner lens, not even glued in very accurately. if you tilt/off-center the lens just a tiny bit, you get the strangest patterns, without being easily able to tell into what direction to correct, and possibly having the impression that there is no "good spot" at all. try again

i didnt try kes or phr lenses yet, but these are what i have in mind for my next bluray

i will report back!

manuel

Ok! Let me know what happens.

And with the PHR spherical lens, if you put it the other way, then it has to be so close to the diode that the spring barely fits.[/quote]
So you put the rounded side TOWARDS the diode?
If you put the flat side towards the diode, will it give you a round beam?

 

[Krutz]

Re: Achieving a smaller beam diameter with 803T op

i think the flat side towards the diode produces a better, less distorted dot (even without any additional lens-elements/fresnels etc).
drop the spring, and use teflon/ptfe tape on the threads, people said that holds the lens precisely as well. take care to not get take between the diode and lens

manuel

 

[Dark_Horse]

Re: Achieving a smaller beam diameter with 803T op

Nice job Jim! ;D

 

[thebucketmouse]

Re: Achieving a smaller beam diameter with 803T op

wow, impressive mod! +1

 

[Bionic-Badger]

Re: Achieving a smaller beam diameter with 803T op

What about the AR coating on the flat side though? Wouldn't it reduce the power and possibly harm the diode?

 

[Spyderz20x6]

Re: Achieving a smaller beam diameter with 803T op

What about the AR coating on the flat side though?  Wouldn't it reduce the power and possibly harm the diode?

Lol, the light is ment to be shining on the flat side...

 

[Jimmymcjimthejim]

Re: Achieving a smaller beam diameter with 803T op

[quote author=Jimmymcjimthejim link=1225571544/20#21 date=1227050700][quote author=Krutz link=1225571544/20#20 date=1227026467]thats the point!
bluray and hd-dvd have a lens-media distance of under one millimeter, which therefore is the focallength of the lens. the lens is a regular lens (aspheric i am sure) with a fresnel-like ringstructure on one side. so if you use the flat side and move it to its focallength to the diode, it should make a nice tiny dot, and perhaps even without distortion. that depends on the angle of the diode (without lens), if its narrow, it will only light through the middle, good part of the lens. either way, you can just cover the bad outer part with the lens nut, or paint, or alu-foil.
for some info about those lenses (there its the KES one):

http://www.fineartradiography.com/hobbies/lasers/blu-ray/optics.html

Objective (disk read) lens with voice-coil focus and tracking servos. This lens is very special and comprises of a zone plate (diffractive element) below a very high numerical aperture objective with a very unique shape.

i did some experiments with lenses too.
some time ago, when i tried, i got those rings as well, and forgot about those objective lenses. now again on it, no rings, a clear spot, and narrow beam! was a 16x dvd burner lens, not even glued in very accurately. if you tilt/off-center the lens just a tiny bit, you get the strangest patterns, without being easily able to tell into what direction to correct, and possibly having the impression that there is no "good spot" at all. try again

i didnt try kes or phr lenses yet, but these are what i have in mind for my next bluray

i will report back!

manuel

Ok! Let me know what happens.

And with the PHR spherical lens, if you put it the other way, then it has to be so close to the diode that the spring barely fits.[/quote]
So you put the rounded side TOWARDS the diode?
If you put the flat side towards the diode, will it give you a round beam?[/quote]
I put the rounded side towards the diode. The beam is a little oval-ish, but it is very hard to tell.
I will try with the flat side towards the diode again, and I'll report the results.

i think the flat side towards the diode produces a better, less distorted dot (even without any additional lens-elements/fresnels etc).
drop the spring, and use teflon/ptfe tape on the threads, people said that holds the lens precisely as well. take care to not get take between the diode and lens

manuel

Again, I'll try it with the flat side towards the diode.

Nice job Jim! ;D

Thanks! I just thought that I would share my modification with everyone.

wow, impressive mod! +1

Thanks for the rep

What about the AR coating on the flat side though? Wouldn't it reduce the power and possibly harm the diode?

Hmm. I wish I had a LPM to test this, but I don't. I'll see how it reflects violet light.

[quote author=Bionic-Badger link=1225571544/20#26 date=1227570217]What about the AR coating on the flat side though? Wouldn't it reduce the power and possibly harm the diode?

Lol, the light is ment to be shining on the flat side...[/quote]
Well yeah, that's the orientation in the sled. But the sled also has red and IR diodes too, so it could be AR coated for them.

 

[Spyderz20x6]

Re: Achieving a smaller beam diameter with 803T op

You said you needed an LPM?
Check out my exclusive sales thread

http://www.laserpointerforums.com/forums/YaBB.pl?num=1225241169

 

[Jimmymcjimthejim]

Re: Achieving a smaller beam diameter with 803T op

You said you needed an LPM?
Check out my exclusive sales thread

http://www.laserpointerforums.com/forums/YaBB.pl?num=1225241169

Lol, yes, that is an amazing price, but I have absolutely no cash at the moment.
I reversed the lens and odd things happened.
To get a parallel beam, you have to screw the lens in all the way. You would think that the dot would be even smaller this way, but it's about the same size. But interesting enough, the odd concentric circle pattern disappeared. Also, the hole of the back of the lens nut limits the size of the beam. I see this because I cut my lens nut to a wide oval shape, and that's the shape of the dot.

 

[Spyderz20x6]

Re: Achieving a smaller beam diameter with 803T op

[quote author=Spyderz20x6 link=1225571544/20#29 date=1227574021]You said you needed an LPM?
Check out my exclusive sales thread

http://www.laserpointerforums.com/forums/YaBB.pl?num=1225241169

Lol, yes, that is an amazing price, but I have absolutely no cash at the moment.
I reversed the lens and odd things happened.
To get a parallel beam, you have to screw the lens in all the way. You would think that the dot would be even smaller this way, but it's about the same size. But interesting enough, the odd concentric circle pattern disappeared. Also, the hole of the back of the lens nut limits the size of the beam. I see this because I cut my lens nut to a wide oval shape, and that's the shape of the dot.[/quote]
Pics please