Generation of a Purely Single Transverse Mode Vortex Beam from a He-Ne Laser Cavity with a Spot-Defect Mirror

<table>Recorded intensity distributions (a) before the waist by 4 times of Rayleigh length and (b) at the waist, respectively. (c) The variations of the beam diameters as a function of the distance from the waist. Open and filled circles indicate the horizontal and vertical beam widths, respectively. Fitting curves are depicted by solid lines.</table>

International Journal of Optics

fig5

Figure 5

Figure 5: Generation of a Purely Single Transverse Mode Vortex Beam from a He-Ne Laser Cavity with a Spot-Defect Mirror 