If you want to buy check on web pages of Bruker, Nicolet or Perkin Elmer. These companies product FTIR spectrometers with different accessories.

I have FTIR spectrometer with PMA50 module (PM-IRRAS) supplied by Bruker. If you give some more details about your project may be I can have some suggestions for you.

Thank you so much for your answer.

Actually, I wanted to see the TO phonon mode of Binary Oxides with Rocksalt structure. They are very thin so I expect to see their phonon modes in the Reflectance.

They are supposed to have a TO phonon mode in Far Infrared regime. Below 500 cm-1.

How thin is very thin? In any way, I would expect that the phonon is so strong that you don't need PM-IRRAS to observe it...

Actually, these films are below 20 nm thick.

I will try today with FTIR in reflectance mode.

Let's see.

Thanks again.

If you have your film on a metal substrate, and film thickness is not much less than 20 nm, it should suffice!

Actually, they are all on insulating substrates.

EuO on LAO

EuO on YAO

EuO on YSZ

And round about 20 nm.

I am looking for a TO phonon mode around 200 cm-1

Ok, this is challenging, because those substrates have themselves strong phonon bands in comparable spectral regions as far as I remember...