What Causes Molecules to Aggregate Over a Fiber in Optical Trapping?

[Sciencestd]

I poured a droplet that has 1.55 refractive index (RF) over a fiber that has core and cladding with (RI) 1.45 and 1.4 respectively, and I the molecules aggregated over the fiber, known that because the refractive index of the liquid is higher than of than of the core or the cladding a leakage of light from fiber to the droplet happens. The number of propagated modes in the fiber is three modes and the diameter is 13 micrometer.

So I have two questions:
1- So why they aggregate over the fiber? What do you think the scenario is?!
2- Does the shape or the polarization of the three modes still the same in the droplet as in the fiber? Because the shape (or the cross section) of the fiber with respect to the surface is arch...

The image on the left depict the experiment and the image on the right shows the cross section of the fiber.

 

[berkeman]

I poured a droplet that has 1.55 refractive index (RF) over a fiber that has core and cladding with (RI) 1.45 and 1.4 respectively, and I the molecules aggregated over the fiber

I am of no technical help yet on your question, but I would like to clarify some of the words in your post and your thread title. Hopefully I can fix up your thread title to attract more attention if the words make more sense to our other users.

So you put a drop of water on top of a thin optical fiber, and saw something happen? What do you mean by this:

and I the molecules aggregated over the fiber

What "molecules"? Water molecules (seems obvious). Light "molecules"? (seems much less obvious). Some other "molecules"?

 

[Sciencestd]

It is a solvent which contains MnTPP molecules and the solution is toluene (the "liquid" that was mentioned above)... yes it is thin fiber embedded in a glass so it is in the same plane with the surface of the glass... the molecules (MnTPP) aggregated over the fiber (the thin fiber)... (The fiber is close to the surface..)