Spherical aberration correction in nonlinear microscopy and optical ablation using a transparent deformable membrane

We describe the design and utilization of a deformable membrane to minimize the negative spherical aberration that occurs when a standard water-dipping objective is used to focus within a higher-index sample. In connection with two-photon laser scanning microscopy, we demonstrate twofold improved axial resolution of structures as deep as 1mm in gels and brain tissue. In conjunction with plasma-mediated ablation, we demonstrate enhanced production of optical damage deep within a glass substrate. The present method provides a simple and inexpensive correction for a limited yet important class of optical aberrations.