A modern take on Koehler

[MichaelG.]

This interesting paper [free PDF download] describes an experimental construction using 4f components:
https://inspirehep.net/literature/1722279

Intended as a teaching-aid, it’s well-described and full of good ideas !

MichaelG.

[BramHuntingNematodes]

Oh yeah I been using those thorlabs aspheric lenses with my LEDs for awhile now they're great and not too pricey.

[MichaelG.]

Although I still commend the paper to anyone with an interest in Koehler illumination … I am rather bewildered by the assertion that it is

low-cost

Comments from those familiar with funding in Academia would be appreciated !

MichaelG.

[SuiGenerisBrewing]

I think the "low-cost" claim is in regards to the lenses and other materials needed to create a Koehler setup on optical tables (which is what I assume they mean by "tabletop systems", rather than those made for conventional microscopes.

I have an optical table that I use for teaching microscopy concepts at my uni. The configuration we use to explain Koehler uses ~$500 worth of lenses and mounts. The setup in this paper would be around half that cost. Not exactly a huge savings, but it is less.

As a comparison, the teaching scopes we have the students use (which have a Koehler condenser, plus phase and dark field) run $6,000 - $8,000 each.

[Macro_Cosmos]

Although I still commend the paper to anyone with an interest in Koehler illumination … I am rather bewildered by the assertion that it is

low-cost

Yeah, it is low-cost. Any proper lab will already have sorted cabinets filled with cage components, so those are "free". The lenses would be another $200 or so, or in my case, $0 because I yoinked them from a dead sequencer.

A new Ti2 or IX73 would be ~$30k with fluorescence options, and no objectives. In perspective, $5k (or their $2k) would be deemed low-cost.
An even lower cost method would involve a dig into their storage for some old microscope to salvage the transmitted light path, $0. No fumbling around with annoying cage systems and no need to align anything or rage when some a...hole dumped imperial screws into the metric drawer. A $5 heatsink with a $5 single-die LED would outperform that dim Thorlabs dinky thing that has horrible cooling and efficiency. The LED can be controlled with a power supply which they definitely have.