1. Apple Inc, 1 Apple Park Way, Cupertino, California 95014, United States
2. Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, U.K.
3. Department of Physics and Astronomy, LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, Amsterdam 1081 HV, The Netherlands
4. Department of Physics, University of York, York YO10 5DD, U.K.
5. Department of Biology, University of York, York YO10 5DD, U.K.