Multichannel Mueller matrix ellipsometer based on the dual rotating compensator principle

Abstract 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 ( ω 1 ) SC 2r ( ω 2 ) A , where P , S , and A represent the polarizer, sample, and analyzer. C 1r ( ω 1 ) and C 2r ( ω 2 ) represent two MgF 2 biplate compensators that rotate at frequencies of ω 1 /2 π =10 Hz and ω 2 /2 π =6 Hz, synchronized for a ratio ω 1 : ω 2 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°.