Low-aberration high-speed-compatible optical delay line

Opt Lett. 2020 Jul 1;45(13):3820-3823. doi: 10.1364/OL.397314.

Abstract

We describe a simple approach to dispersion-free optical delay line design that provides very low aberration over an extended delay range. In this approach, we minimize aberrations by directing non-axial beam displacements along a line of symmetry built into the apparatus. We show improved performance and significant reduction of wavefront aberrations by comparing simulation and experimental results with a similar delay line that lacks this line of symmetry. The new design facilitates transform-limited recovery of spectral resolution in Fourier transform coherent anti-Stokes Raman scattering, and accordingly, we demonstrate 3.5cm-1 spectral resolution with a 10 ps delay scan range.