Focusing Optical systems 6 Imaging systems 4 Lenses 4 Liquid crystals 4 Aberrations 2 Annular lenses 2 Apodization 2 Approximation theory 2 Atom-surface collision 2 Best image plane (BIP) 2 Chiral-achiral interfaces 2 Coherence-length 2 Coherent light 2 Data processing 2 Depth of focus 2 Diffraction efficiency 2 Dynamic range 2 Equivalent aberrations 2 Equivalent defocus 2 Fourier transforms 2 Fringe visibility 2 Image analysis 2 Image quality 2 Incoherent monochromatic light 2 Interfaces (materials) 2 Interferometers 2 Irradiance distribution 2 LCoS display 2 Lateral resolution 2