Imaging with Waves
Creating images with light camera obscuramodern imaging device
Steering waves Magnification with 2 lenses
Seeing small things Antonie van Leeuwenhoek
The compound microscope
Seeing sharper
Modern optical microscopy
Focusing down Airy Disk 0.61 /NA NA = nsin 22
The diffraction limit Objects spaced apart by less than d~ /2NA cannot be resolved individually! Ernst Abbe ( )
Imaging with the diffraction limit ObjectImageFocal spot Images can be improved by using shorter wavelengths
CD versus DVD 7x more data on DVD because of different wavelength! 780 nm650 nm (Blu-Ray DVD uses 405 nm, 6x more data than DVD)
UV lithography
Superresolution
Single molecules
Seeing single molecules at work
Seeing smaller things using particlesusing EM radiation of particles: Electron with v = 1.0 x 10 5 m/s:
Electron Microscopy Resolution ~ 0.2 nm
Electron Microscopy
Cryo-Electron Microscopy
Viral DNA portal protein
What are X-rays? Wilhelm Conrad Röntgen ( ) Electromagnetic radiation with wavelength of ~ m
Focusing or diffracting? Bragg diffractionDiffraction pattern 2d sin = n
X-ray crystallography
Protein structure determination X-ray crystallography reveals electron densities
Protein structure determination
No longer a mystery
DNA polymerase on the DNA backbone