From Reinhard Schinke

Lasers: N 2 >>N 1 B 21 W(  ) A B 23 W p (  ) A 21 A 23

Lasers: N 2 >>N 1 B 21 W(  ) A 13 fast B 23 W p (  ) A 21 slow A 23 Pump Lase

Nd 3+ :Y 3 Al 5 O 12 (YAG)

Cavity—2 mirrors separated by n /2 Lasers characterized by: Directionality Monochromatic Brightness Coherence Discuss: Threshhold

Linewidths Homogeneous Broadening: Affects every molecule the same way e.g. time energy uncertainty principle and pressure broadening   h   1 sets a minimum linewidth of  -1 Expressed as e -t/  decay of final state probability the corresponds after Fourier transform to a Lorentzian lineshape FWHM= 

Linewidths Inhomogeneous broadening: Collection of molecules have a distribution of transition energies. Typically given by statistics of different molecular environments and described by Gaussian functions. FWHM=2  (2ln2) e.g. Doppler Broadening

–Mon Feb 18 Presidents day –Weds: Rayleigh and Raman Scattering –Weds Feb 27: Projects Part1