Review of Laser (1)
1, how does radiation interact with matter?
2, how to prepare system to have gain?
3, how do EM waves propagate in space and resonate in cavities?
paraxial wave equation:
solutions of vector Helmholtz equation, and scalar wave equation
SVEA: slowly varying envelope approximation
2 methods to solve PWE: standard diffraction theory or direct solution
paraxial form of a spherical wave
complex curvature of a Gaussian beam:
spherical wave front and Gaussian radial profile
angle of diffraction of a Gaussian beam increases from 0 at z=0
to
Gouy’s phase: phase of the beam shifts by 90 degree from z=0 to infinity
Rayleigh range defines the boundary between near field and far field:
in the near field, plane wave with Gaussian envelope;
in the far field, spherical wave with origin at z=0 with a Gaussian envelope
diffracting as
Fourier transform of a Gaussian is still a Gaussian
Higher order Gaussian beams: complete solutions are Hermite-Gaussian modes,
modes, it has n zeros in x and m zeros in y
March 7th, 2009 at 5:08 am
上帝说，要有光，于是就有了光；
上帝说，还要有鸡，于是就有了激光
March 11th, 2009 at 12:59 am
老张,你很油墨!