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Entry  Thu Mar 4 17:04:52 2021, Paco, General, Design specs, Silicon TM dichroic coatings for phase I ETM_coating_candidates.pdfITM_coating_candidates.pdf
    Reply  Wed Mar 17 19:51:42 2021, Paco, General, Design specs, Silicon TM dichroic coatings for phase I ETM_R_210317_1927.pdfETM_Layers_210317_1927.pdfETM_nominal_cornerPlt.pdf
       Reply  Wed Mar 17 21:24:27 2021, gautam, General, Design specs, Silicon TM dichroic coatings for phase I 
          Reply  Wed Mar 24 17:36:46 2021, Paco, General, Design specs, Least common multiple stacks and varL cost ETM_Layers_210323_0925.pdf
             Reply  Fri Apr 2 19:59:53 2021, Paco, General, Design specs, Differential evolution strategies diffevostrategies.pdf
                Reply  Fri Jun 4 11:09:27 2021, Paco, General, Design specs, HR coating tolerance analysis 
          Reply  Wed Mar 24 17:42:50 2021, Paco, General, Design specs, Silicon TM dichroic coatings for phase I 
Message ID: 6     Entry time: Wed Mar 17 19:51:42 2021     In reply to: 4     Reply to this: 7
Author: Paco 
Type: General 
Category: Design specs 
Subject: Silicon TM dichroic coatings for phase I 

Update on ETM

New optima are being found using the same basic code with some modifications, which I summarize below;

  1. Updated wavelengths to be 2128.2 nm and 1418.8 nm (PSL and AUX resp.)
  2. The thickness sensitivity cost "sensL" previously defined only for 2128 nm, is now incorporating AUX (1418 nm) in quadrature; so sensL = sqrt(sens(2128) ** 2 + sens(1418)**2)
  3. There is now a "starfish" plot displaying the optimized vector cost. Basically, the scores are computed as the inverse of the weighted final scalar costs, meaning the better stats reach farther out in the chart. One of these scalar costs does not actually belong to the optimization (stdevL) and is just a coarse measure of the variance of the thicknesses in the stack relative to the average thickness.
  4. Included a third wavelength as transOPLV (for the OPLEV laser) which tries to get R ~ 99 % at 632 nm
    1. Imagine,... a third wavelength! Now the plots for the transmissivity curves go way into the visible region. Just for fun, I'm also showing the value at 1550 nm in case anyone's interested in that.
  5. Adapted the MCMC modules (doMC, and cornerPlot) to check the covariance between the transmissivities at 2128 and 1418 for a given design.
  6. Reintroduced significant weights for TO noise and Brownian noise cost functions (from 1e-11 to 1e-1) because it apparently forces solutions with lower thickness variance over the stack (not definitive, need to sample more)

Still working to translate all these changes to ITM, but here are samples for some optimum.

  • Attachment 1 shows the spectral reflectivity/transmissivity curves with a bunch of labels and the transparent inset showing the starfish plot. Kind of crazy still.
  • Attachment 2 shows the stack. Surprisingly not as crazy (or maybe I have internalized the old "crazy" as "normal")
  • Attachment 3 shows a very simple corner plot illustrating the covariance between the two main wavelengths transmissions.
Attachment 1: ETM_R_210317_1927.pdf  133 kB  Uploaded Wed Mar 17 21:07:07 2021  | Hide | Hide all
Attachment 2: ETM_Layers_210317_1927.pdf  26 kB  Uploaded Wed Mar 17 21:07:11 2021  | Hide | Hide all
Attachment 3: ETM_nominal_cornerPlt.pdf  82 kB  Uploaded Wed Mar 17 21:07:46 2021  | Hide | Hide all
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