Question

What is the difference between unpolarised light waves and polarised light waves?

Answer 1

Looking at a single photon can be tough, but if you do so, you will find it's polarized.

What I mean by polarized ? The locus of the extremity of the Electric field moves in a particular fashion, if you look at them into the direction of their propagation:

be it linearly polarized:

Or be it circular:

or be it elliptical:

But, they all are fully polarized.

Because, the field is a vector quantity, this "regularity" demands certain relationship between the amplitudes and the phases of the x- and y- components of the Electric field. If they abide by those, they are polarized light. But,

If you are looking at the light coming from sun (don't do it literally, it is bad for your eyes) you will see, there are many many photons, and hence many electric fields, if you look at the total field extremity, it moves crazily:

It is like a homogeous mixture of every kind of polarized lights. Lets say, you pick linearly polarized photons who are oriented in every directions and give them random amplitudes and phases (remember, we needed exact relationships of them for the light to be polarized) . And now you mix them. That is the unpolarized light .

Hope this helps