Low-cost set-up for Fourier-transform infrared spectroscopy in diamond anvil cell from 4000 to 400 cm-1

An experimental set-up for Fourier-transform infrared (FTIR) studies at high pressure in the mid-IR region (400-4000 cm(-1)) is constructed using a compact TEO-400 FTIR interferometer module and an external microscopic optical bench with cassegrain focusing objectives. Cassegrain-type reflective objectives act as an excellent beam condenser that facilitates the interfacing between FTIR spectrometer and diamond anvil cell. This set-up is capable of recording transmission and reflection infrared spectra at high pressure. Preliminary results are reported both in the reflection (pressure dependence of polar phonons in CuWO4) and transmission configuration (polarized light absorption of polar phonons across the wurtzite-to-rocksalt transition in ZnO).