Fig. 4: Proof of principle experiments.
From: Memory effect assisted imaging through multimode optical fibres
a Experimental set-up to measure the full TM of an MMF, emulate ATM measurement with a guide-star, and image through the MMF using the full TM and ATM. HW half wave-plate, QW quarter wave-plate, BS beamsplitter, PBS polarising beamsplitter, SF spatial filter. Supplementary Note 3 provides a more detailed description of the set-up. b Fully sampled TM of an MMF represented in PIM basis. The scale-bar is the same as that used in Fig. 1, and here indicates the amplitude (encoded in brightness) and phase (encoded in colour) of each matrix element. Inset shows an enlarged region of the TM indicating the fine structure around the main diagonal. Supplementary Fig. 4 shows an enlarged plot of this TM. Supplementary Movie 1 shows the input and output fields used to fully sample the TM, which also visually highlights the symmetries present in the MMF transform. Power ratio maps of scanned foci using the fully sampled TM (c) and guide-star based ATM (d). The scale-bar indicates the power-ratio across the distal facet. Guide-star location is marked with a red circle. e–g Example transmission images of a resolution target obtained with the fully sampled TM. The location where the resolution target is inserted at the distal facet of the fibre is marked with an O. h–j Examples of transmission images of the same scene as (e–g), in this case obtained with guide-star based ATM. The scale-bar indicates the relative intensity of the reconstructed images. Supplementary Movie 2 shows the focus being scanned in 2D across the isoplanatic patch at the distal facet of the MMF.
