I wouldn't have thought it would be much different from gold:  the electron density is similar.  The critical parameter is the extinction distance.  By the way,  10 nm Au is definitely visible,  there is already noticeable absorption. 

What do you mean by "transparent"?  I think 100 nm Au is still transparent in the sense you can see through it.  Half-silvered mirrors are "transparent" - essential in their use as beam splitters!

Lior,

Here you may find the transmission of Pt film:

Thin-Film Optical Filters, Third Edition - Page 170 - Google Books Result

books.google.co.il/books?isbn=1420033239

H.A. Macleod - 2001 - ‎Technology & Engineering

Platinum films on glass 5 10 20 50 Physical thickness of platinum (nm) Figure 4.7. ... The transmission of a metal film is the same, regardless of the direction in ...

See also attached file with the graph. According to it, about 5 nm Pt film is 50% transparent

Boris, thank you very much! 

Chris, thank you for your input

I'd be happy with >50% transmission or higher in the vis, but I could probably do with half of that as well.

The trade-off is that I wouldn't want to approach the thickness where I should be concerned whether the films are continuous.

When the films are less than about 5-10 nm they are discontinuous  - the exact behavior depends on the substrate and temperature.  For discontinuous films, transmission and reflection are more wavelength dependent - in particular you can get an absorption feature.  For thicker films, reflection is strong.  Transmission can be enhanced by using an antireflection layer.  This is much researched for silver in the context of low-e coatings.  

B. Meyler is right. Actually, I found the same answer with him. I agree with him.

I remember that we have had an old Leybold evaporator in our lab where the (optical) transmission is used for an estimation of the film thickness. Of course this depends on the wavelength, but I made the experience that in the case of Pt (as well as for Au and Ag) a film of more than 20 nm in thickness is almost "non-transparent", i.e. it has maybe 10% transmission or less. So 5-10 nm should result in a quite large transparency (50%), but, as Andre mentioned above, it is difficult to prepare continuous films in this thickness range. Pt (as well as Au and Ag) tend to show 3d-growth on glass (due to the low interaction / adhesion between Pt and the glass), resulting in isolated particles. If the substrates are heated, this may lead to discontinuous materials for even thicker films!

So, in conclusion, try to deposit a film of substantially less than 20 nm, and see if it fits to your expectations. Good luck, Dirk

Transparent to what ? be specific, working in EUV range, 2-5 nm could be enough transparent but with high absorbtion in the VUV range (100-150 nm). Have a look on the C-XRO website for more information (henke.ibl.gov/optical_constants/) in this UV range.

Then you have also to take into account of the feasability of your depostion method. Using E-B, you are quite limited. Trying using ALD deposition , you'll improve your requirements.

Good luck.

I agree with B. Mayler.

Dear Lior,

According to our experiments a 5 nm thick Pt layer exhibits transmittance of 45–50% in the visible light region. I hope this help you.

Maria

Thank you all for the valuable input.

If you will not doing transmission experiments, it is helpful to have a non-transparent Pt layer.  

I have used the Ep4 Model were we still have an iformation of the layer thickness of PT layer till 30 nm (using spectroscopic ellipsometry)

So till 30 nm pt thickness it will be still transparent.

Best regards

Christian

I have an updated question for this discussion .. what was the wavelength for these thickness ? I am trying to estimate the transparency of Pt to 325 nm laser .. any ideas how transparent would a 50 nm thick Pt film be ? 

I model it with Ep4model with Platin on SiO2 in Transmission Ellipsometry for 30, 50 70, 90 nm thickness. Values for T (parallel) are attached in the jpeg.

Best regards

Christian

Dear Christian,

thanks for the file .. what is the X-axis range 

Oh i Forget to added. It rangeing from 300-400 nm (wavelength).

Best regards

Christian