Spatial Filter

[alan.bogana]

Hi everybody,

I would like to buy a spatial filter (ideally for max 500$) in order to use it with a 40x objective (like this from Edmund: 40X DIN Plan Commercial Grade Objective - Stock #43-908) and a 15micron Pinhole.
Any suggestion on models or somebody who's selling used ones ?
On Ebay there are some stuff but it's hard to understand what is compatible with what (sorry, I started holography only some months ago).

This affordable Edmund model only work with max 20x (after verification with the Edmund staff)...
http://www.edmundoptics.com/lasers/lase ... ment/1291/

Best regards
Alan

[BobH]

The two problems I have found when using spatial filters with 40x objectives are 1) the nose of the objective hitting the pinhole mount before the pinhole is at the focal point, and 2) the diverging beam coming out of the pinhole hits the pinhole mount and makes a glowing ring around the source. Problem #1 is not there with old Jodon spatial filters. With Newport 910 spatial filters, I remount the pinhole on the input side of the mount with tape. Old Newport 900 models may be fixed the same way.

Problem #2 is difficult. With old Jodon devices, I drilled out a pinhole mount so it wouldn't happen. The same approach will probably work with other models, but each one will be different. A glowing ring around the reference source is not a good thing.

Here's a nice Jodon unit with pinhole for a good price. I'd offer him $100 and see what he says. http://www.ebay.com/itm/Signed-Jodon-LP ... 4ae68fb175

[jsfisher]

I have couple of Newport spatial filters that are surplus. One is the 900 model without pinhole. The other is a 910 without objective.

When I am no longer at the place that is not home, I will take a couple of photographs and recheck how smoothly the adjustments move. (If I remember correctly, the pinhole positioner on the 910 was stiff, but the all the other micrometers and knobs worked well.)

[Paulos]

I am very satisfied with the spatial filter from HOLMARK (an Indian producer).
Model number SFA-S http://holmarc.com/spatial_filter_mounts.php
Good quality, with micrometer movement and NOT expensive. About five years ago, I paid ca. USD140 each new.
Additionally, it is very versatile: The distance between the two plates (for the microscope objective and for the mounted pinhole) is adjustable.
They also have a website http://www.holography.in dedicated to holography.

[jsfisher]

I was right about one thing and wrong on another. The 910 pinhole adjustment is a bit stiff, but it also has a 10x objective.

[jsfisher]

Ouch!! Those images are a little large. Let's try something more modestly scaled.

[alan.bogana]

Hi,

Great!

Bob, thank you very much for your insightful advices ! That Jodon unit could definitely be an option.

Jsfisher, thank you. Could you tell me the price you’re selling them please ?

Paulo, thank you very much for this address ! I will definitely look into this option as well

Cheers
Alan

[Paulos]

.......The distance between the two plates (for the microscope objective and for the mounted pinhole) is adjustable.

I should write:
The MIN and MAX distance between the two plates (for the microscope objective and for the mounted pinhole) is adjustable, so that also longer or shorter than normal microscope objectives can be used.

[admin_jsfisher]

Jsfisher, thank you. Could you tell me the price you’re selling them please ?

I was thinking US$250 for either one, US$400 for both. I think I know where in the world you are located, so I can probably include shipping, too.

(If others think I'm being unreasonable, say so. I am not looking to be excessive.)

[alan.bogana]

Thank you again for the proposal, which I think is a good price! Tempting, but for simplicity reasons I'll go with another option.
Cheers
Alan