Recent content by eliasds

  1. E

    Undergrad Calculate focused spot size - Gaussian FWHM

    Anyone else have a more detailed answer?
  2. E

    Undergrad Calculate focused spot size - Gaussian FWHM

    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...
    • eliasds
    • Thread
    • Fwhm Gaussian
    • Replies: 2
    • Forum: Optics
  3. E

    Proof of Divergence Formula in Spherical Coordinates

    Phi is the angle in the page, and the theta is the angle out of the page.
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    Proof of Divergence Formula in Spherical Coordinates

    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...