[Laser] last message was 8/12/2016?

[Chuck Hast]

Nuu, no paper, just a question. I am building a spectrograph to measure the
wavelength of lasers I am incorporating into some tools.

Some years back I built one to determine the wavelength of lasers I was
using
in glass container inspectors. The thing was spot on, I checked the device
using a DPSS laser at 532nm, and a HeNe at 632.8nm. In both cases it was
well within 5nm of what it should have been.

I have built one just recently, but I am not getting anywhere near the
precision
I was getting with the one back then. I have tested it with one of the DPSS
lasers I used on the original one. I do not have a HeNe here at this moment
so not sure where the red end is.

The  original used a grate at 300 L/mm, figuring on greater accuracy I
bought
the 1000 L/mm grate.

The series of test I have done have given me about 548nm for a 532nm DPSS
laser, that is way off. The only real difference between the original
instrument
and this one is the grating is 1000 L/mm, the original was 300 L/mm. The
only
thing that I can suspect is the 1000 L/mm is NOT 1000 L/mm but something
more. I guess I will have to reverse the calculations and see if I can
determine
the real number of lines/mm.

I may also buy a 300 L/mm grate, then I will have it all the same as the
original.


Wonder if anyone else has run into this sort of thing.



On Sat, May 12, 2018 at 11:01 AM, John McNulty <john at generalrobots.com>
wrote:

> Greetings All,
>
> Perhaps there’s a learned paper title forthcoming?
>
> "Loop-back Latency in Laser Links" ;-)
>
> Best Wishes to All,
>
> J McN
>
> > On 12 May 2018, at 15:48, Glenn Thomas <glennt at gbis.com> wrote:
> >
> > FWIW, the last message I had on this group was August 12, 2016...
> >
> > On 5/12/2018 7:33 AM, Zack Widup wrote:
> >> I'm still here. Haven't seen any activity on this group in ages. Go
> ahead
> >> with your question!
> >>
> >> 73, Zack W9SZ
> >>
> >>
> >
> > --
> > "i" before "e" except after "c", or when sounded as "a" as in neighbor
> and weigh.
> >
> > This rule is “counterfeit”. General spelling rules “forfeit” generality.
> > They are “foreign”, being not “either” or “neither”, possibly the result
> of some
> > “leisure” activity of a “sovereign heir” who, lacking “height”, is
> studying,
> > without “conscience, inefficient glacier science”. It’s not as
> nutritious
> > as "protein". It's just plain old "weird"
> >
> > Is this example “sufficient”?
> >
> >
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-- 

Chuck Hast  -- KP4DJT --
I can do all things through Christ which strengtheneth me.
Ph 4:13 KJV
Todo lo puedo en Cristo que me fortalece.
Fil 4:13 RVR1960