# What is meant by the component sinusoids being "correlated"?

I am currently studying Optics, fifth edition, by Hecht. Chapter 2.11 Twisted Light says the following:

Such beams have what’s called an azimuthal ($$\phi$$) phase dependence. Looking down the central axis toward the source the phase changes with angle, just as the time on a clock face changes with the angle $$\phi$$ between the vertical 12–6 line and the minute hand. If a component-wave peak occurs at 12, as in Fig. 2.32, a trough might occur directly beneath the axis at 6. Examine the diagram carefully, noticing that as it goes from 12 to 1 to 2 to 3 and so on the wavelets advance. Their phases are all different on the slice; they’re each shifted successively by $$\pi/6$$. The disc-shaped slice cuts across the beam but it is not a surface of constant phase, and the overall disturbance is not a plane wave. Still the component sinusoids (all of wavelength $$\lambda$$) are correlated and all of their peaks lie along a spiral.

What is meant by the component sinusoids being "correlated"? Does that mean that, since we know that the the wavelet phases shift successively by $$\pi/6$$, we can determine a relationship for how other wavelets would relate to any one?