Multichannel Mueller matrix ellipsometer based on the dual rotating compensator principle

A multichannel ellipsometer in the dual rotating-compensator configuration has been designed and constructed for applications in real time Mueller matrix ellipsometry (approx. 2-5 eV) of anisotropic surfaces and films. The sequence of optical elements for this instrument is denoted PC_1r(ω₁)SC_2r(ω₂)A, where P, S, and A represent the polarizer, sample, and analyzer. C _1r(ω₁) and C_2r(ω₂) represent two MgF₂ biplate compensators that rotate at frequencies of ω₁/2π=10 Hz and ω₂/2π=6 Hz, synchronized for a ratio ω₁:ω₂ of 5:3. Spectra in the 16 Mueller matrix elements of a transmitting or reflecting sample can be established from the 25 non-zero Fourier coefficients of the irradiance waveform acquired in a single 0.25 s optical cycle. Initial high speed Mueller matrix measurements have been performed on weakly anisotropic samples that push the instrument to its precision/accuracy limits. These include the (110) Si surface with maximum cross-polarization ellipsometric angles of ψ_ps∼0.1° and nanostructured thin films with maximum ψ_ps∼1°. © 2003 Elsevier B.V. All rights reserved.