Beam divergenceformula

Determining the exact diameter of the beam is difficult, because the beam intensity is reduced with 1/(distance)2, and over the beam cross section it decays almost exponentially (Gaussian shape) toward the edges. More accurate measurement is by subtracting the laser beam diameter at the laser output (d) from the measured value (D), and call it the new value (D*). Draw a graph of D* vs. L. Calculate (on the data sheet) the slope of the graph. Calculate (on the data sheet) the angle of divergence of the laser. Repeat steps 1 through 6 with the Diode laser.

More accurate measurement is by subtracting the laser beam diameter at the laser output (d) from the measured value (D), and call it the new value (D*). Draw a graph of D* vs. L. Calculate (on the data sheet) the slope of the graph. Calculate (on the data sheet) the angle of divergence of the laser. Repeat steps 1 through 6 with the Diode laser.