[DIYbio] Re: Discussion: DIY SEM/FIB

On Wed, Oct 21, 2009 at 8:19 AM, Simon Quellen Field <sfield@scitoys.com> wrote:
> HF is not necessary.
> Electro-etching in salt water works fine.
>
> I assume everyone interested in this has already seen
> "http://www.geocities.com/spm_stm/Project.html"
> "http://www.springerlink.com/content/24341g648g00128u/"
>
> I have some ideas for a scanning near-field optical microscope I have been
> meaning
> to try for a while now, but it is a little too ambitious for my current
> audience. The idea
> is to fix a single molecule of something fluorescent to a microscope cover
> slip, and
> vibrate it horizontally using a speaker or piezo element, On top of that is
> another
> cover slip with the sample fixed to it, face down towards the fluorescent
> molecule.
> A sub-wavelength layer of immersion oil separates the sample from the
> molecule.
>
> The sample is vibrated vertically, so you have a raster. An avalanche
> photodiode
> or a photomultiplier tube sits above the sample, with a low pass optical
> filter
> keeping out the ultraviolet from an ultraviolet LED below that excites the
> molecule.

Did you ever try this? There's a professor in Portland who I believe
is doing something similar, except pulsing a laser at the vibrating
piezo, and an optical raman edge filter (these are high pass I
believe). There was a lock-in amplifier somewhere too, I think, but
that might have been for controlling the piezo frequency. I can't
rememeber.

This is one of his papers, it mentions that the laser is a cheap CW
laser pointer type:
http://diyhpl.us/~nmz787/pdf/Apertureless_near-field_far-field_CW_two-photon_microscope_for_biological_and_material_imaging_and_spectroscopic_applications.pdf

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