For helium neon laser, which has a beam waist of 0.5mm, what will be the value of near field and far field conditions?
How does the intensity in a Gaussian beam vary as it propagates? The optical intensity is a function of axial and radial distances. Axial distances are the distances along the propagation direction, whereas radial distances are the distances in the transverse plane. On the beam axis, it varies as: Where Io is the maximum value at z=0 i.e. beam waist and drops gradually with increasing z, reaching half its value at z = zR i.e. Rayleigh distance. When z>> zR, The intensity decreases with the distance in accordance with the inverse square law. In the transverse plane, the intensity distribution is of the form: Where Imax is the value of intensity at that value of z, r is the radial distance from the axis and wor is the beam waist radius. Maximum intensity is at a point where z = 0 and r = 0, i.e. at the center of the beam waist. Relations between pulse width, energy, pulse repetition rate and power. Peak pulse power (W) = Pulse energy (Joules) / Pulse width (sec) Average Power (W) = : Pul
