Linear and Nonlinear Spectroscopy by a Common-Path Birefringent Interferometer

We introduce a passive common-path interferometer to replace Michelson interferometers in the Fourier-transform spectroscopy. Our device exploits birefringence to introduce a highly accurate delay between two orthogonal polarization components by continuously varying the material thickness. Due to its inherent delay stability and reproducibility, it can be used even for short wavelengths (down to ...