[Laser] Chucks question continued

Tue May 15 17:20:16 EDT 2018

Found it. Interesting.

On Tue, May 15, 2018 at 9:06 AM, Jim Moss <n9jim-6 at pacbell.net> wrote:

> Mike found a spectrometer on eBay.
> New they are about $150, and there is a $70 model as well. From a French
> company Thunder Optics.
> Jim
>
> Sent from my iPhone
>
> > On May 14, 2018, at 9:44 PM, Chuck Hast <wchast at gmail.com> wrote:
> >
> > Jim,
> > Looks like I missed something did not see anything from Mike just saw
> > your response. Is it some sort of spectrograph or spectrometer?
> >
> >
> >> On Mon, May 14, 2018 at 11:32 PM, Jim Moss <n9jim-6 at pacbell.net> wrote:
> >>
> >> Mike,
> >> Looks like that is pretty cheap.
> >> Looks like it is about 3nm resolution, and about 2 month delay to
> shipment.
> >> You have to calibrate it yourself.
> >> Might be interesting.
> >> Let us know how it goes.
> >> Jim
> >>
> >>
> >> Sent from my iPad
> >>
> >>> On May 14, 2018, at 8:08 PM, Chuck Hast <wchast at gmail.com> wrote:
> >>>
> >>> Jim,
> >>> That did it. Now to go through it and get it into a stand alone little
> >>> piece of
> >>> say python code. A good exercise for me...
> >>>
> >>> Then the larger angle was probably what was taking a bite out the
> >> numbers in
> >>> the original calculation using the formula that you indicated was doing
> >> the
> >>> approximation.
> >>>
> >>>
> >>>> On Mon, May 14, 2018 at 8:21 PM, Jim Moss <n9jim-6 at pacbell.net>
> wrote:
> >>>>
> >>>> Chuck,
> >>>> It looks like we may have sin and tan issues here
> >>>>
> >>>> Original cited article:
> >>>> http://laserclassroom.com/products/measure-wavelength-laser-light/
> >>>>
> >>>> The angle based on your data is arctan(627/1000) = 32.08771207 Degrees
> >>>> That’s diffraction distance (X) / distance to target (L)
> >>>>
> >>>> The grating equation is WL = d sin(32.08771207), d=1000/mm
> >>>> Or 531.2 nM.  That matches your laser source.
> >>>>
> >>>> Note that in your original cited article approximates sin = tan.
> >>>> This is true when the angle is small, but introduces errors at larger
> >>>> angles.
> >>>>
> >>>> Here’s a calculator for the experiment: not using the approximation.
> >>>> http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/gratcal.html
> >>>>
> >>>> Jim
> >>>>
> >>>> Sent from my iPad
> >>>>
> >>>>> On May 14, 2018, at 5:40 PM, Jim Moss <n9jim-6 at pacbell.net> wrote:
> >>>>>
> >>>>> Chuck,
> >>>>>
> >>>>> After rereading, I think my statement on d is not correct. It may be
> as
> >>>> simple as 1 mm/1000. See link below to Newport.
> >>>>>
> >>>>> Could the error be related to that you are not reflecting directly
> off
> >>>> the grating surface? The experiment shows sending the beam thru the
> >>>> grating? If so, could there be an angle error induced?
> >>>>>
> >>>>> Could it be that the grating is facing the wrong way? Thus creating
> an
> >>>> offset due to the medium thickness of the grating material?
> >>>>>
> >>>>> Good summary on defraction gratings.
> >>>>> https://www.newport.com/t/grating-physics
> >>>>>
> >>>>> Jim
> >>>>>
> >>>>>
> >>>>> Sent from my iPad
> >>>>> ______________________________________________________________
> >>>>> Laser mailing list
> >>>>> Home: http://mailman.qth.net/mailman/listinfo/laser
> >>>>> Help: http://mailman.qth.net/mmfaq.htm
> >>>>> Post: mailto:Laser at mailman.qth.net
> >>>>>
> >>>>> This list hosted by: http://www.qsl.net
> >>>>> Please help support this email list: http://www.qsl.net/donate.html
> >>>> ______________________________________________________________
> >>>> Laser mailing list
> >>>> Home: http://mailman.qth.net/mailman/listinfo/laser
> >>>> Help: http://mailman.qth.net/mmfaq.htm
> >>>> Post: mailto:Laser at mailman.qth.net
> >>>>
> >>>> This list hosted by: http://www.qsl.net
> >>>> Please help support this email list: http://www.qsl.net/donate.html
> >>>>
> >>>
> >>>
> >>>
> >>> --
> >>>
> >>> 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
> >>> ______________________________________________________________
> >>> Laser mailing list
> >>> Home: http://mailman.qth.net/mailman/listinfo/laser
> >>> Help: http://mailman.qth.net/mmfaq.htm
> >>> Post: mailto:Laser at mailman.qth.net
> >>>
> >>> This list hosted by: http://www.qsl.net
> >>> Please help support this email list: http://www.qsl.net/donate.html
> >>
> >> ______________________________________________________________
> >> Laser mailing list
> >> Home: http://mailman.qth.net/mailman/listinfo/laser
> >> Help: http://mailman.qth.net/mmfaq.htm
> >> Post: mailto:Laser at mailman.qth.net
> >>
> >> This list hosted by: http://www.qsl.net
> >> Please help support this email list: http://www.qsl.net/donate.html
> >>
> >
> >
> >
> > --
> >
> > 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
> > ______________________________________________________________
> > Laser mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/laser
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:Laser at mailman.qth.net
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Laser mailing list
> Home: http://mailman.qth.net/mailman/listinfo/laser
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Laser at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

-- 

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