Hpls245

According to Eq. (2), to correctly map from the numerically reconstructed surface to the original wavefront, an accurate calibration of the distance z is important and necessary. The exact distance is calibrated and characterized in another separate experiment as described in Fig. 8. This is accomplished by comparison between our numerical reconstruction wavefronts and the ground truth wavefronts. Figure 8(a) shows the optical setup, where a plasma broadband white light source (HPLS245, Thorlabs) is used for illumination. A pre-calibrated reflective phase-only spatial light modulator (SLM) (PLUTO-2-VIS-016, Holoeye) is configured to interpret grayscale images as 2π phase wrapping, for generating ground truth wavefronts. Some examples are shown in Fig. 8(b). A linear polarizer ensures the SLM operates in the pure phase modulation mode. The relay lenses (two f = 125 mm cemented achromatic doublets, AC254-125-A, Thorlabs) conjugate the SLM to the wavefront sensor plane at ×1 magnification ratio. By comparing the algorithm output wavefronts with the ground truth in Fig. 8(b), and with the known sensor pixel size 6.45 μm and SLM pixel size 8 μm, for each slope the calibrated distances are computed as in Fig. 8(c), where their mean is z = 1.43 mm.

Mid-log phase cultures of Synechocystis PCC 6803 and Cyanothece PCC 7425 cells harboring the pSB2TΔKm^R-gfp, pSB2T-ccmk1_tsbp1-gfp and pSB2T-maf_S6803-gfp plasmids were placed in sandwiches consisting of two glass coverslips (22 mm diameter, Paul Marienfeld GmbH & Co. KG) one of which being coated with a Poly-L-lysine (Sigma-Aldrich) monolayer. These coverslip sandwiches were sealed and placed inside a home-made sample holder, which was mounted on a Nikon Ti-U inverted microscope coupled with an iXon ULTRA 897 CCD camera (Andor Technology), equipped with a 100x oil immersion (NA 1.45) microscope objective. Epifluorescence images were recorded using an excitation provided by a plasma light source (HPLS245 Thorlabs, Inc.) and an excitation filter (MF469-35 Thorlabs, Inc.), while for super-resolution laser scanning images a 488 nm laser (OBIS, Coherent) was used as an excitation source.
Chlorophyll and GFP fluorescence were recorded using ET655LP (Chroma Technology Corporation) and MF525/39 (Thorlabs, Inc.) emission filters, respectively.