Fig. 1
The secondary beam path captured on CAM2 is used for monitoring and sample targeting, which is easier to perform on the image plane than on Fourier plane. A long coherence (approx. 3 mm) diode laser illuminates samples in a 96-well plate mounted on a heated stage. The 10x objective then collects the diffusely scattered light, which is directed to a holographic diffraction grating at the Fourier plane, which splits the incoming field into multiple diffraction orders. The positive and negative first order diffractions are passed through spatial filters to obtain a cropped object field and a point-like reference field, which are optically Fourier transformed again and captured on the Camera.
