Strange results with transfer matrix (Optics)

In summary: Your Name]In summary, the individual is experiencing high reflectance values in their transfer matrix code for certain wavelengths when there is a thin film present between two absorbing media. They have already checked their code and compared it to other simulations, but are still unsure of the cause. Possible explanations include not properly accounting for the absorption coefficient of the materials, the thickness of the thin film, or the angle of incidence of the light. It is suggested to further troubleshoot and consult with experts or the developers of the code for assistance.
  • #1
Olioli
2
1
Hi everyone,

I'm trying to study reflection on the rear side of an optical device. I wrote a transfer-matrix code in MATLAB to compute the reflectance. I checked my code by comparing some basic cases with other kind of optical simulations (FTDT with Lumerical). When the incident medium is Air or Dielectric materials, I got relevant results (both transfer matrix or FDTD give the same). When I only have one interface (like Silicon-aluminum), My code gives the same solution than the one obtains with Fresnel coefficients. The problem appears when I introduce thin films between two absorbing medium. For example, Silicon-MgF2-Aluminum interfaces, where silicon is the incident medium and Aluminum the substrate. For some wavelength, the reflectance (so the amount of light reflected in the silicon) is higher than 1, which is of course wrong (no luminescence in transfer matrix code).

I don't know what's wrong with transfer matrix. This problem appears only when the incident and substrate medium are absorbing and a dielectric layer are inserted between them.
pnmP2Vwxp.png
 
Science news on Phys.org
  • #2
Can someone please help me understand what is going on and how I can fix this issue?
Hi there,

It sounds like you have already done some thorough testing and troubleshooting of your code, which is great. One possibility could be that your transfer matrix code is not taking into account the absorption coefficient of the materials, which could lead to higher reflectance values for wavelengths where there is significant absorption. It may be helpful to double check your code and make sure you are incorporating the absorption coefficient correctly.

Another potential issue could be the thickness of your thin film. If the film is too thin, it may not be able to fully absorb the incident light, leading to higher reflectance values. I would suggest varying the thickness of the film and seeing if that affects the results.

It's also worth considering the angle of incidence of the light. If the light is at a high angle of incidence, it may increase the path length through the absorbing materials, leading to higher reflectance values. Again, varying the angle of incidence could help determine if this is a factor in your results.

I hope these suggestions are helpful in troubleshooting your code and resolving the issue. If you continue to have trouble, it may be helpful to consult with other experts in the field or reach out to the developers of the transfer matrix code for further assistance.

Best of luck with your research!
 

Related to Strange results with transfer matrix (Optics)

Question 1: What is a transfer matrix in optics?

A transfer matrix in optics is a mathematical tool used to analyze and predict the behavior of light as it passes through various optical elements, such as lenses, mirrors, and prisms. It describes the relationship between the input and output light parameters, such as intensity, polarization, and direction.

Question 2: Why are my transfer matrix results strange or unexpected?

There can be several reasons for strange transfer matrix results, including errors in the input parameters, incorrect assumptions or simplifications in the model, or limitations of the transfer matrix method itself. It is important to carefully check all input parameters and assumptions to ensure the accuracy of the results.

Question 3: How can I improve the accuracy of my transfer matrix calculations?

To improve the accuracy of transfer matrix calculations, it is important to use accurate and precise input parameters, such as refractive indices and thicknesses of optical elements. It can also be helpful to use more complex transfer matrix models that account for additional optical effects, such as multiple reflections or diffraction.

Question 4: Can transfer matrix calculations be used for all types of optical systems?

No, transfer matrix calculations are most useful for analyzing simple, planar optical systems with parallel input and output beams. They may not accurately predict the behavior of more complex or non-parallel systems, such as curved or non-planar surfaces, or systems with significant diffraction effects.

Question 5: Are there any limitations to using transfer matrix calculations in optics?

Yes, there are some limitations to using transfer matrix calculations in optics. As mentioned before, they may not accurately predict the behavior of complex or non-parallel systems. Additionally, they may not account for all optical effects, such as scattering or absorption, and may not be accurate for highly nonlinear systems. It is important to carefully consider the limitations of the transfer matrix method when using it for optical analysis.

Similar threads

Replies
19
Views
4K
Replies
1
Views
1K
  • Electrical Engineering
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
2K
Replies
1
Views
1K
  • Advanced Physics Homework Help
Replies
8
Views
6K
  • Classical Physics
Replies
1
Views
751
Back
Top