Posted on January 13, 2020February 9, 20202D Electronic Spectroscopy Using Rotating Optical Flats Paper describing the 2D spectrometer design was published in The Journal of Physical Chemistry A (DOI: 10.1021/acs.jpca.0c00285). The accepted version of the manuscript can be downloaded here, along with the supporting information. Layout of the 2D spectrometer. CM: concave mirrors, DO: 2-dimensional diffractive optic, ND: neutral density filter, DG: delay glass, CW: chopper wheel, ROFs: rotating optical flats, BB: beam block. The positions of the laser pulses are labeled with kn and LO. The third-order signal (red line) is emitted from the sample on the same path as the LO (dotted line).