[OpenSPIM] WG: Re: About the lightsheet

Thu Dec 5 09:30:44 CST 2013

 Hi Jan,

I changed the order of the lens in the telescope so that it expands the beam and I got a thinner lightsheet, but when I move the mirror mounted on the sample holder in the X direction
the lightsheet expands too much. I attach some images.

Do you know if I can adjust the relationship between the thickness of the lightsheet in the center and in the borders of the FOV using the vertical slit?

Kind regards,
Edgar

 _________________________________________________________________________

Fraunhofer-Institut für Produktionstechnologie IPT 
Edgar Escobar Nieto  

Steinbachstraße 17 
52074 Aachen 

edgar.escobar.nieto at ipt.fraunhofer.de 
http://www.ipt.fraunhofer.de
_________________________________________________________________________

-----Weitergeleitet von Edgar Escobar Nieto/Fraunhofer IPT am 05.12.2013 15:53 -----
An: Jan Krieger <j.krieger at dkfz-heidelberg.de>
Von: Edgar Escobar Nieto/Fraunhofer IPT
Datum: 04.12.2013 17:37
Betreff: Re: [OpenSPIM] About the lightsheet

 Hi Jan,

Yes, I am talking about the telescope between the corner mirror and the objective.

Ohh, I have thought that this telescope instead of expanding the beam, it was reducing it.
In the instructions of how to install the telescope from the OpenSPIM wiki, the 50 mm focal length lens goes first and then
the 25 mm, (the opposite order in comparisson to the beam expander). So, it looks like all this time I have been using the
wrong lens configuration. 

Concerning the pictures, I am always using the illumination objective, in some using the telescope (between the corner mirror and the objective), in others without using it.

That explain everything. I will change the order of the lenses of the last telescope in order to expand the beam and not to reduce it. Thanks a lot for your answer.
I will let you know if I suceed.

Kind regards,
Edgar

 _________________________________________________________________________

Fraunhofer-Institut für Produktionstechnologie IPT 
Edgar Escobar Nieto  

Steinbachstraße 17 
52074 Aachen 

edgar.escobar.nieto at ipt.fraunhofer.de 
http://www.ipt.fraunhofer.de
_________________________________________________________________________

-----Jan Krieger <j.krieger at dkfz-heidelberg.de> schrieb: -----
An: "edgar.escobar.nieto at ipt.fraunhofer.de" <edgar.escobar.nieto at ipt.fraunhofer.de>
Von: Jan Krieger <j.krieger at dkfz-heidelberg.de>
Datum: 04.12.2013 15:39
Betreff: Re: [OpenSPIM] About the lightsheet

Hi!

hhmmm ... I pressume you're talking about the telescope between the 
corner mirror and the objective, right?

As far as I know the openSPIM, this telescope should lead to an 
additional 2-fold expansion of the beam. This means that the light fills 
more of the projection objective and should thus also create a thinner 
focus (we "use more" of the available NA of the objective ... ) ... So 
your finding of with and without the objective looks strange to me ... 
Can you measure the width of the lightsheet with your different 
configurations? It should slightly expand, if you move the 45°-mirror 
along the lightsheet axis ... How did you find the right position of the 
projection objective? We usually find a sharp line on the mirror and 
position it in the center of the FOV, then adjust the lightsheet to 
overlay with this line, using the corner mirror and finally adjust the 
projection obvjective (along the lightsheet axis) until we have the 
thinnest possible lightsheet which should then also have it's thinnest 
position in the center of the FOV.

Best,
JAN

Am 04.12.2013 15:18, schrieb edgar.escobar.nieto at ipt.fraunhofer.de:
> Hi dear all,
>
> I have made some tests about the lightsheet. I made some pictures of the
> lightsheet using the telescope and without using it. To be able of
> imaging the lightsheet I used a small mirror at 45° mounted in a sample
> holder to direct the lightsheet onto the CCD.
>
> I found that the lightsheet looks narrower without using the telescope.
> I know that the telescope is used for alignig the lightsheet with the
> focal plane of the detection objective in
> an easier way (adjusting the knob of the last mirror causes the
> lightsheet to move parallel to the plane of the detection objective
> without being tilted).
>
> I found out that also is possible to align the lightsheet without using
> the telescope. Then, I aligned the lightsheet rotating the knob of the
> mirror but also translating it (I have mounted the mirror in a rail as
> in this picture http://openspim.org/File:1I_1D_OpenSPIM_03.jpg ). To be
> sure that the lightsheet was perpendicular to the detection axis
> throughout the complete FOV I made some pictures of the lightsheet
> moving the mirror mounted in the sample holder in the X direction.
>
> I attach the pictures to this mail. In the pictures can be observed that
> the lightsheet is directed to the part of the mirror mounted in the
> sample holder that is in focus. Even if I translate the mirror mounted
> in the sample holder in the X direction, the lightsheet remains on the
> focused part. This is the way I check that the lightsheet is
> perpendicular throughout the complete FOV. When the lightsheet was not
> completely perpendicular I observed that the lightsheet was not
> reflected exactly on the part in focus when moving the mirror in the X
> direction.
>
>  From the pictures without using the telescope, it can be observed that
> the lightsheet widens in the borders of the FOV (because of the gaussian
> nature of the lightsheet), but in the pictures where I use the
> telescope, the lightsheet seems to be the same thickness along the
> complete FOV.
>
> I would like to know if what I have done is right and why does the
> lightsheet does not seem to change its thickness in the borders of the
> FOV when I use the telescope.
>
> Kind regards,
> Edgar
> _________________________________________________________________________
>
> Fraunhofer-Institut fr Produktionstechnologie IPT
> Edgar Escobar Nieto
>
>
>
>
> Steinbachstraáe 17
> 52074 Aachen
>
> edgar.escobar.nieto at ipt.fraunhofer.de _
> __http://www.ipt.fraunhofer.de_ <http://www.ipt.fraunhofer.de/>
> _________________________________________________________________________
>
> 	
> 	
>

[Anhang 'j_krieger.vcf' entfernt von Edgar Escobar Nieto/Fraunhofer IPT]

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