[Q] The way of phase shifting of reflection light

[good_phy]

Hi, I learned optics with pedrotti optics book.

It is suppopsed that light is reflected on surface of first layer and

then tranmited wave is also reflected on surface of second layer, So there is Double Layer

incident light get there.


According to book, If two reflections are both external reflection or internal reflection,

Phase shift is not occurred (Assume thickness of layer alone is well to make OPL(Optical Path

Length) of two beam in phase)


But If two reflections are either external or internal, Phase shift of Pi occured.


I know boundary condition of medium for EM wave create phase shift of Pi when wave is

reflected on the surface of some medium


But this knowledge alone is not able to explain phenomena mentioned above.


Please Solve my question.

 

[Doc Al]

I know boundary condition of medium for EM wave create phase shift of Pi when wave is reflected on the surface of some medium

For light of normal incidence, the phase shift upon reflection depends on the refractive index of the medium: If light reflects from a medium of greater refractive index, there will be a phase shift of pi; if it reflects from a medium of lower refractive index, there is no phase shift.

(I'm not sure if this addresses your question, but it might help.)

 

[astrokreng]

Hello,

Thank you for sharing your question and explaining your understanding of optics and phase shifting of reflection light.

From what you have described, it seems like you are referring to the phenomenon of interference, where multiple waves of light overlap and create a resulting wave with a different amplitude and phase. In the case of reflection, this can occur when light is reflected off two surfaces, such as in a double layer or multiple layer setup.

The phase shift that you have mentioned is a result of the difference in optical path length (OPL) between the two beams of light. When the OPL is equal, the waves are in phase and no phase shift occurs. However, when there is a difference in OPL, the waves are out of phase and a phase shift of Pi (180 degrees) occurs. This can be explained by the boundary conditions of the medium, as you mentioned.

I would recommend looking into the concept of interference and how it relates to phase shifting in reflection. There are also other factors that can affect the phase shift, such as the angle of incidence and the refractive index of the medium.

I hope this helps to answer your question. Keep exploring and learning about optics, it is a fascinating field of study. Best of luck to you in your studies.