I apologize if my question does not make sense.(I'm teaching myself microscopy.)
So reading Fundamentals of Light Microscopy and electronic imaging by Douglas&Murphy, at one point the author mentions that light can be described as electromagnetic waves and then gives a picture similar to this one
Later on, when describing the "quality of light"(I quote him) he writes:
The kinds of light most frequently referred to in this text include:
• Monochromatic. Waves having the same wavelength or vibrational frequency (the same color).
• Polarized. Waves whose E vectors vibrate in planes that are parallel to one another. The E vectors of rays of sunlight reflected off a sheet of glass are plane parallel and are said to be linearly polarized.
• Coherent. Waves of a given wavelength that maintain the same phase relation ship while traveling through space (laser light is coherent, monochromatic, and polarized).
• Collimated. Waves having coaxial paths of propagation through space—that is, without convergence or divergence, but not necessarily having the same wave- length, phase, or state of polarization. The surface wavefront at any point along a cross-section of a beam of collimated light is planar and perpendicular to the axis of propagation.
My confusion stems from the paragraph when the author describes polarized light. In the general form of the waves, given in the picture, the electric field vectors are parallel. So, all light should be polarized, right?
Also, regarding the image describing the waves, does the pink arrow(which is a straight line), which is parallel to the x-axis(Am I right?) describe the path of a photon?