- I have imported my experimental data to OptiChar. I load the data and in fitting window I see that the data are zero. I see the reasonable model transmittance shown by the black curve and measurement transmittance close to zero. What am I doing wrong?
Please check transmittance units. Probably, in OptiChar settings you set up % for R/T. At the same time experimental transmittance was recorded in your data file in absolute units. If so, go to General Configuration --> Units tab and change T/R units from % to 0-1. Then repeat data import. Specific data import options (Varian, PerkinElmer, X/Y files) allow to set units in the course of the data import procedure, without necessity to change global configuration settings.
- I want to design a coating with specified color properties in VIS and specified target transmittance in the NIR-IR. Is it possible to take into account two types of targets simultaneously?
Yes, of course, in OptiLayer you can combine targets of various types, for example, color and conventional (as in your case) or color and integral, or integral and conventional. For each target you can specify own spectral range. In the latest version you can balance targets using weight coefficient (see more…)
- I am going to correct refractive index of my high index material in the course of reverse engineering. In the Indices Correction option, I have a choice between constant drift, linear drift and exponential drift. It is my understanding that constant drift is index offset? Is it correct?
Yes, you are right. Index drift in this context is index offset. These are two different notations of the same thing. If you choose this option, it means that in the course of your reverse engineering procedure, OptiRE will look for a model refractive index with refractive index offset. Learn more…
- I am a beginner in OptiLayer. I design a coating using Needle Optimization AUTO, but I see that my design contains several thin layers. When I remove them simultaneously, approximation of my target is getting worse essentially. Maybe I am doing something wrong?
OptiLayer provides two options (Thin Layer Removal and Design cleaner) which allow you automatically remove thin layers. Of course, design performance is getting worse but in these options you are able to control merit function increase. In some cases, it may happen that some of these thin layers are very important for the design. You may try more advanced design strategies in order to get rid of thin layers (see our paper).
- I am performing post-production characterization of a produced multilayer sample on the basis of T/R data measured in the range from 320 nm to 1500 nm. In Fitting Window I observe that fitting in the range from 320 to 400 nm is very bad. At the same time fitting in the range 400-800 nm is normal. I have looked at Refractive index window and seen that refractive index is a constant in the range from 320 to 400 nm.
If refractive index is constant in 320-400 nm spectral range, it means that you specified refractive index starting with 400 nm only. Please check this. If refractive index dispersion is not specified in a spectral range, then OptiLayer automatically use a constant for calculations in this range. The constant is equal to the refractive index value at the boundary of the spectral range. In your case, refractive index in the range from 320 to 400 nm was taken equal to n(400nm). In order to observe fitting of your experimental data by model data, you have to know refractive index in the whole spectral range of interest. For this purpose, you can produce single layer samples and determine refractive index in the range from 320 to 850 nm using OptiChar.
- I need to design a narrow band pass filter containing only quarter-wave layers. Is it possible with OptiLayer?
Yes, for your purpose you can try WDM design option. See more…
- I have to design a beamsplitter merged between two glasses. How can I specify this structure in OptiLayer?
You need to load you glass as a substrate and also as an incident medium.
- I have a problem to design a color coating. Target colors are specified in LAB system, light source is D65. I have my own program that computes some coating characteristics. I calculated color coordinates in my program and compared with OptiLayer results for the same test multilayer (100 nm and 200 nm, refractive indices 2.35 and 1.45, substrate refractive index is 1.52). My LAB coordinates for R(normal incidence) are a*=16.39, b*=18.06, L*=45.06, OptiLayer gives a*=21.11, b*=21.32, L*=45.73. I see the differences. I am sure that my program calculates correctly, all optical constants (refractive indices of materials and substrate) are the same as in OptiLayer. Where is the problem?
You did not load D65 light source and it was not included into OptiLayer calculations. Actually, if we do not include the light source, we obtain a*=16.39, b*=18.06, L*=45.06. If we include it, we obtain exactly the same values that you show a*=21.11, b*=21.32, L*=45.73.
- I have measurement data from a Woollam ellipsometer. I have Psi, Delta and also R/T. What is more convenient: to record all these data in the same measurement file or to import the data into different files? I am asking because I want first to process Psi, Delta and R/T separately.
I can do by any of these two ways. If you import all the data into one file, you can use Modify Measurements option and temporarily remove, for example, R/T data before your characterization process. Or, you can save the data into separate files and, in the case if you want to see all fitting simultaneously you can use Append to Loaded option and append R/T data to Psi/Delta fitting.