You don't need to know every work on your topic before you know your topic. When starting research, look for a few highly relevant articles and reviews. I suggest trying to find 5-10 items to read after a review of several dozen abstracts. Once you have found some articles that are truly specific to your work, you can use forward and backward citation search to work through the literature.
I will use Web of Science for this example.
The article, Accelerated Amidization of Branched Poly(ethylenimine)/Poly(acrylic acid) Multilayer Films by Microwave Heating opens new window has great potential to be relevent to your project.
A quote from the experimental section of the article is
For fitting of these ellipsometric data, a Cauchy layer was used to describe the optical constants of the BPEI/PAA film.(36)Reference 36, Spectroscopic Ellipsometry Characterization of Indium Tin Oxide Film Microstructure and Optical Constants opens new window has this important data on how the Cauchy model was actually used to fit the ellipsometric data – this is simply not presented and a curious researcher would be expected to look this up.
After examining the Synowicki article from 1998, you notice in the conclusion that
More exact fits can be achieved over a wider spectral range by modeling the film with a graded profile and using Lorentz oscillators to describe the refractive index at the top and bottom of the film.
From the citations given in the Lorentz section of this paper, you decide to examine the book, Optical Properties of Solids by Wooten from 1972, to help decide whether the Cauchy method or Lorentz method is most appropriate for your work.
After examining the Synowicki article from 1998, you wonder who else used this Cauchy method to fit ellipsometric data. You look it up on Web of Science and see that it has been cited over 200 times (among the publications they pay attention to):
If you select the "221 Times Cited" hyperlink to the right of the article, you get a list of publications that cited this article. If you were interested in optics, you could search for the keyword, or refine in the left side of Web of Science under the categories option:
The point is that you can find who cited a work that you find useful and interesting, and possibly find more relevant material. Then, you can go backwards into other works cited.