Recent content by eliasds

Anyone else have a more detailed answer?

http://www.calctool.org/CALC/phys/optics/f_NA Does anyone know how they calculate the spot size (Gaussian FWHM) at this website? For a plane wave, the focused spot size it approx=2*wavelength*f/(pi*d0) f=focal length of lens d0=collimated beam diameter before lens but how do you...

Phi is the angle in the page, and the theta is the angle out of the page.

Hello - I'm supposed to derive the divergence formula for spherical coordinates by carrying out the surface integrals of the surface of the volume in the figure (the figure is a piece of a sphere similar to a box but with curves). The radial coord is r. The polar angle is \varphi and the...