Temporal stabilization module inside MicAO 3DSR Audrius JASAITIS, Cynthia VEILLY and Fabrice HARMS Imagine Optic, 18 rue Charles de Gaulle, 91400 Orsay, France [email protected] Summary It is well known that the shape of thin reflective membrane deformable mirrors, and, eventually, their generated wavefront depends on the variation of the ambient temperature in the laboratory. This is not problematic when the deformable mirror is operated in a closed-loop mode because its shape is constantly adjusted using the information from the wavefront measurement. But the variation of surrounding temperature becomes much more important when the deformable mirror is operated in an open-loop mode, especially when the shape has to be kept constant to a very high precision for over 1 hour, as it is sometimes the case in single molecule localization microscopy techniques. Here we present the characterization of a modified Mirao 52e deformable mirror including athermalization for optimal temporal stability regarding temperature variations. Even when the ambient temperature in the room changed by more than four degrees, the shape generated by the modified Mirao 52e deformable mirror did not cause any visible changes of astigmatism in the PSF (less than 10nm RMS total wavefront change). The stabilization module greatly improved the temporal stability of Mirao 52e deformable mirror, thus greatly simplifying super-resolution imaging routine performed with a MicAO 3DSR adaptive optics device. MicAO 3DSR stabilization module Technical note www.imagine-optic.com 24 January 2019 – Property of Imagine Optic

MicAO 3DSR is an adaptive optics device designed for easy there is no continuous feedback about the actual wavefront to the deformable mirror. The typical imaging microscope and camera and its primary task is to optimize time frame in PALM/STORM methods is about 1 hour, the point spread function (PSF) by correcting aberrations in enough time to acquire 50k-300k frames that are used for the whole optical system. The main application of MicAO a reconstruction of the super-resolved structure. In 3DSR is 3D single molecule localization microscopy (SMLM) common laboratory environments, such a time...

market there is a variety of available deformable mirrors, which are using very different architectures and therefore they may be affected differently by the ambient temperature variation. Temperature variation can cause changes in focus, appearance of astigmatism, spherical aberration or coma. In the case of Mirao 52e deformable mirror, the main aberration which appears with temperature change is astigmatism. Depending on the way the membrane is assembled, the orientation of astigmatism is different and it is a generally a superposition of both astigmatism at 0° and astigmatism at 45°. In Figure...

Figure 4. Example images of the diffraction-limited fluorescent bead at different ambient temperature. The 60nm RMS of astigmatism was added using the deformable mirror. Middle row – the bead is in focus, the upper and lower rows - the bead is slightly out of focus. stabilization module was switched off during the night and localization precision and the reconstruction accuracy had to re-stabilize the next morning. The only difference that starts to be visible in the PSF in SMLM methods over very long experiments. • imaging sequences which increases the versatility and due to temperature change...