What you're describing is light traveling sinusoidally in the xy-plane, and longitudinally along the z-axis. It's trajectory can be somewhat modeled as u(x(t),y(t),z(t)) = <sin(t),cos(t),t>. There I did most of the math for you, doing the actual experiment should be incredibly easy. And if you prove that light travels in such a manner you will be rich and famous beyond your imagination. Now go and publish your work in a peer reviewed journal, and wait for the Nobel prizes to pour in.
Unless, of course, you're speaking out of your ass and know nothing about physics, and instead of looking at the evidence and coming to a conclusion, you've already come to a conclusion and now you're doing fantastic mental and logical gymnastics to support your conclusion. How's that, am I in the ballpark?