How is the diffraction efficiency of a transmission hologram calculated?
In this paper is information regarding of diffraction efficiency calculation.
The (ideal) theoretical diffraction efficiency of a hologram is usually defined to be the ratio of the intensity I(r) projected to position r relative to the designed intensity I_D(r) at that point, averaged over all points in a specified plane. The theoretical projected field often is computed in scalar diffraction theory as the Fourier transform of the field in the hologram plane (i.e. the hologram itself). The projected intensity is then the squared magnitude of the calculated field.
The efficiency of pixellated holograms also should take into account the influence of any gaps between the pixels, which tend to reduce diffraction efficiency. The pixels' form factor can be incorporated into a model for the hologram before performing the efficiency calculation.
Finally, the overall diffraction efficiency of a transmission hologram is reduced by reflection from the front surface. Generally, this is an overall scale factor that can be calculated with the Fresnel reflection and transmission formulas.
I do not understand the subject of this discussion. The paper is a kind of a piece from some textbook for the students. So what?
Vladimir Venediktov @ The paper - is help to student (Bini) who have just started to learn science. Therefore, the paper for him. If you have the desire to put a more complicated issue, you can do this. I wish you success in organizing the debate.
Strange situation... Maybe I still do not understand the essence of this forum. I have always thought that this is a place where people can ask some questions, and somebody, who knows the subject better, can advise them. Sorry if I have misunderstood the sence of posting here this rather strange paper (no author, no reference points etc.)
Dear Vladimir,
In my opinion, this forum have a broad spectrum of questions, including also those questions which you mentioned. In this concrete case we have the student' question. Above mentioned paper is information for him only. He demand some knowledge. We must to help him. I am sure, that this forum is a very interesting and useful. I'm sure you'll soon see this.
Best regards,
Yuriy
Yuriy,
unfortunately too often nowadays students prefer to post questions in forums vs using the internet and the library to get the information. Yes books still exist, even if many people seems to forget that. In most cases questions are so silly that people could easily find the answer themselves and just post here the more technical issue about them (before asking, just google for that or show how you did the calculation or how you imagine it can be done, for ** sake!).
I don't mind spending hours explaining things to a student that shows he tried hard to find an answer to a question, but I do not accept to waste my time doing his job if he did not even try. And I am sorry, but this is exactly the case here! For instance, you've been able to find that document on the internet, so the student MUST and SHOULD have found it himself even before thinking of asking any question here
Matteo,
I totally agree with you, and so I gave only a reference to lecture published in Google. It would be good that this case was instructive for Beni, and other similar students. It should also be noted that in many cases, students do not respond on the answer. It is not known whether they read the answer to your question?
Yuriy
I would like to note that classical Kogelnik’s expressions for diffraction efficiency of the volume hologram do not work in practice due to the absorption during recording. We studied this problem in the paper: Lyubavskaya I.K., Serov O.B., and Smolovich A.M. Effect of Absorption of the Recording Beams on the Diffraction Efficiency on Thick-film Holograms. Sov. Tech. Phys. Lett., 1980, V.6, N.1, 16-18.
Article Effect of Absorption of the Recording Beams on the Diffracti...
- Badges
- Science topic
- Similar topics
- Mathematics
- Algebra
- Matrix