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Guest
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 Posted:
Wed May 11, 2005 4:35 pm Post subject:
Focused homemade nitrogen laser? |
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I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?
Bob Clark
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Dirk Bruere at Neopax
Guest
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| Posted:
Wed May 11, 2005 4:35 pm Post subject:
Re: Focused homemade nitrogen laser? |
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rgregoryclark@yahoo.com wrote:
| Quote: | I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?
|
Quartz lens?
--
Dirk
The Consensus:-
The political party for the new millenium
http://www.theconsensus.org |
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Sam Goldwasser
Guest
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| Posted:
Wed May 11, 2005 9:42 pm Post subject:
Re: Focused homemade nitrogen laser? |
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Dirk Bruere at Neopax <dirk@neopax.com> writes:
| Quote: | rgregoryclark@yahoo.com wrote:
I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?
Quartz lens?
|
The problem isn't the lens material as much as the beam quality. It will be
hard to focus the typical home-built N2 laser's output to a very small spot.
--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html
Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.
Important: Anything sent to the email address in the message header above is
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Dirk Bruere at Neopax
Guest
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| Posted:
Wed May 11, 2005 9:47 pm Post subject:
Re: Focused homemade nitrogen laser? |
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Sam Goldwasser wrote:
| Quote: | Dirk Bruere at Neopax <dirk@neopax.com> writes:
rgregoryclark@yahoo.com wrote:
I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?
Quartz lens?
The problem isn't the lens material as much as the beam quality. It will be
hard to focus the typical home-built N2 laser's output to a very small spot.
|
Depends on the length of the laser cavity I assume, since its single pass.
--
Dirk
The Consensus:-
The political party for the new millenium
http://www.theconsensus.org |
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Sam Goldwasser
Guest
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| Posted:
Wed May 11, 2005 10:08 pm Post subject:
Re: Focused homemade nitrogen laser? |
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Dirk Bruere at Neopax <dirk@neopax.com> writes:
| Quote: | Sam Goldwasser wrote:
Dirk Bruere at Neopax <dirk@neopax.com> writes:
rgregoryclark@yahoo.com wrote:
I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?
Quartz lens?
The problem isn't the lens material as much as the beam quality. It
will be hard to focus the typical home-built N2 laser's output to a
very small spot.
Depends on the length of the laser cavity I assume, since its single pass.
|
More than that. It depends on the mode structure of the beam.
--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html
Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.
Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs. |
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Mark Fergerson
Guest
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| Posted:
Wed May 11, 2005 10:14 pm Post subject:
Re: Focused homemade nitrogen laser? |
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Sam Goldwasser wrote:
| Quote: | Dirk Bruere at Neopax <dirk@neopax.com> writes:
Sam Goldwasser wrote:
Dirk Bruere at Neopax <dirk@neopax.com> writes:
rgregoryclark@yahoo.com wrote:
I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?
Quartz lens?
The problem isn't the lens material as much as the beam quality. It
will be hard to focus the typical home-built N2 laser's output to a
very small spot.
Depends on the length of the laser cavity I assume, since its single pass.
More than that. It depends on the mode structure of the beam.
|
I was going to mention mirror quality and how they're positioned
vs. cavity proportions...
Mark L. Fergerson |
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Uncle Al
Guest
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| Posted:
Thu May 12, 2005 12:24 am Post subject:
Re: Focused homemade nitrogen laser? |
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rgregoryclark@yahoo.com wrote:
| Quote: |
I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?
|
337 nm. Fused silica, alkali halide, or alkaline earth fluoride
lens. A meniscus lens is preferred to lessen aberrations. Down to
microns is gonna take some work - superradiant lasers are not coherent
and you'll need a large diopter rating (thick lenses are problems on
several fronts). I doubt Fresnel or binary optics configurations can
pull it off, especially if you need imaging in addition to
concentration.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf |
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Uncle Al
Guest
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| Posted:
Thu May 12, 2005 12:27 am Post subject:
Re: Focused homemade nitrogen laser? |
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Mark Fergerson wrote:
| Quote: |
Sam Goldwasser wrote:
Dirk Bruere at Neopax <dirk@neopax.com> writes:
Sam Goldwasser wrote:
Dirk Bruere at Neopax <dirk@neopax.com> writes:
rgregoryclark@yahoo.com wrote:
I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?
Quartz lens?
The problem isn't the lens material as much as the beam quality. It
will be hard to focus the typical home-built N2 laser's output to a
very small spot.
Depends on the length of the laser cavity I assume, since its single pass.
More than that. It depends on the mode structure of the beam.
I was going to mention mirror quality and how they're positioned
vs. cavity proportions...
|
Superradiant nitrogen lasers have messy output, as such or one pass
with a rear mirror. The cavity is irrelevant. The output is not
coherent. You might as well try focusing a flashbulb to a few microns
image radius.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf |
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John Fields
Guest
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| Posted:
Thu May 12, 2005 12:35 am Post subject:
Re: Focused homemade nitrogen laser? |
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On Wed, 11 May 2005 15:17:07 -0700, AES <siegman@stanford.edu> wrote:
| Quote: | In article <42825C8D.CBD4B3BD@hate.spam.net>,
Uncle Al <UncleAl0@hate.spam.net> wrote:
Superradiant nitrogen lasers have messy output, as such or one pass
with a rear mirror. The cavity is irrelevant. The output is not
coherent. You might as well try focusing a flashbulb to a few microns
image radius.
Never actually played with one of these, but my hypothesis would be that
if you used a long cavity -- longer the better -- with flat or
long-radius mirrors (radius longer than the mirror spacing) and equal
sized apertures at each end, the angular spread in the output would be
roughly equal to the angular spread of either aperture seen from the
center of the aperture at the other end. Would be a bit delicate to get
and keep the mirrors aligned, however.
|
---
Mirrors???
Apertures???
--
John Fields
Professional Circuit Designer |
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Raymond Yohros
Guest
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AES
Guest
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| Posted:
Thu May 12, 2005 12:35 am Post subject:
Re: Focused homemade nitrogen laser? |
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In article <42825C8D.CBD4B3BD@hate.spam.net>,
Uncle Al <UncleAl0@hate.spam.net> wrote:
| Quote: |
Superradiant nitrogen lasers have messy output, as such or one pass
with a rear mirror. The cavity is irrelevant. The output is not
coherent. You might as well try focusing a flashbulb to a few microns
image radius.
|
Never actually played with one of these, but my hypothesis would be that
if you used a long cavity -- longer the better -- with flat or
long-radius mirrors (radius longer than the mirror spacing) and equal
sized apertures at each end, the angular spread in the output would be
roughly equal to the angular spread of either aperture seen from the
center of the aperture at the other end. Would be a bit delicate to get
and keep the mirrors aligned, however. |
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Gary Cavie
Guest
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| Posted:
Thu May 12, 2005 12:35 am Post subject:
Re: Focused homemade nitrogen laser? |
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In article <42825C8D.CBD4B3BD@hate.spam.net>, UncleAl0@hate.spam.net
says...
| Quote: | Mark Fergerson wrote:
Sam Goldwasser wrote:
Dirk Bruere at Neopax <dirk@neopax.com> writes:
Sam Goldwasser wrote:
Dirk Bruere at Neopax <dirk@neopax.com> writes:
rgregoryclark@yahoo.com wrote:
I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?
Quartz lens?
The problem isn't the lens material as much as the beam quality. It
will be hard to focus the typical home-built N2 laser's output to a
very small spot.
Depends on the length of the laser cavity I assume, since its single pass.
More than that. It depends on the mode structure of the beam.
I was going to mention mirror quality and how they're positioned
vs. cavity proportions...
Superradiant nitrogen lasers have messy output, as such or one pass
with a rear mirror. The cavity is irrelevant. The output is not
coherent. You might as well try focusing a flashbulb to a few microns
image radius.
|
As a young boy, about 8 or so, I read about lasers, and spent many weeks
pocket money buying up loads of toy magnifying glass lenses, stacking
them in a piece of PVC waste pipe, and fitting a torch at one end. Can
you imagine my disappointment when I didn't end up with a laser gun from
'Star Wars'? |
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Baugh
Guest
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| Posted:
Thu May 12, 2005 5:34 am Post subject:
Re: Focused homemade nitrogen laser? |
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Sam Goldwasser wrote:
| Quote: | Dirk Bruere at Neopax <dirk@neopax.com> writes:
rgregoryclark@yahoo.com wrote:
I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?
Quartz lens?
The problem isn't the lens material as much as the beam quality. It will be
hard to focus the typical home-built N2 laser's output to a very small spot.
|
Cannot you by placing the lens far enough away from the laser obtain a
better focus? The distance will correlate off-line output with lateral
displacement. A lens of sufficient quality and wide enough for the
spread beam will then redirect more accurately to the focus.
Think of it in terms of the focused image for the distance to the laser
will move closer to the focus from infinity as you move the lens farther
away. (Again assuming no spherical aberation in the lens.)
Regards,
James Baugh. |
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Sam Goldwasser
Guest
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| Posted:
Thu May 12, 2005 6:33 am Post subject:
Re: Focused homemade nitrogen laser? |
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Uncle Al <UncleAl0@hate.spam.net> writes:
| Quote: | Mark Fergerson wrote:
Sam Goldwasser wrote:
Dirk Bruere at Neopax <dirk@neopax.com> writes:
Sam Goldwasser wrote:
Dirk Bruere at Neopax <dirk@neopax.com> writes:
rgregoryclark@yahoo.com wrote:
I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?
Quartz lens?
The problem isn't the lens material as much as the beam quality. It
will be hard to focus the typical home-built N2 laser's output to a
very small spot.
Depends on the length of the laser cavity I assume, since its single pass.
More than that. It depends on the mode structure of the beam.
I was going to mention mirror quality and how they're positioned
vs. cavity proportions...
Superradiant nitrogen lasers have messy output, as such or one pass
with a rear mirror. The cavity is irrelevant. The output is not
coherent. You might as well try focusing a flashbulb to a few microns
image radius.
|
Well, it's not quite that bad. Most of the light is confined to the
area of the the long narrow discharge gap.
--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html
Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.
Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs. |
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| Back to top |
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Sam Goldwasser
Guest
|
| Posted:
Thu May 12, 2005 6:38 am Post subject:
Re: Focused homemade nitrogen laser? |
|
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Baugh <baconbaugh@charter.net> writes:
| Quote: | Sam Goldwasser wrote:
Dirk Bruere at Neopax <dirk@neopax.com> writes:
rgregoryclark@yahoo.com wrote:
I've seen the designs for low-cost home-built nitrogen lasers. But
these were for unfocused beams.
Is there a low-cost method to focus the beam to a spot in the range of
say a few hundred microns wide?
Quartz lens?
The problem isn't the lens material as much as the beam quality. It
will be
hard to focus the typical home-built N2 laser's output to a very small spot.
Cannot you by placing the lens far enough away from the laser obtain a
better focus? The distance will correlate off-line output with lateral
displacement. A lens of sufficient quality and wide enough for the
spread beam will then redirect more accurately to the focus.
Think of it in terms of the focused image for the distance to the laser
will move closer to the focus from infinity as you move the lens farther
away. (Again assuming no spherical aberation in the lens.)
|
You're not imaging the output aperture of the laser, you're trying to focus
the beam from the laser. As such, how far away you are isn't very relevant.
However, if you're implying that a large f-number lens is better. Sure.
I'm not sure I'd go so far as to say they aren't coherent asn other posts
have stated, but there is a most one bounc from a rear mirror (which isn't
essential) and the light makes at most two passes through the laser. This
doesn't set up a nice mode structure. As everyone's stated, it is messy.
Maybe he'd be better off finding a surplus excimer laser. :)
--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html
Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.
Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs. |
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