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| = Tuning FP modal frequencies using a thermal phase error correction feedback system = | = Tuning Fabry-Perot cavity modal frequencies using controlled thermoelastic deformations on mirror surface = |
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| To compensate for imperfections that arise due to optical inhomogeneities in the arm cavity mirrors by designing and implementing a thermal compensation system. | |
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| 2. Sources of inhomogeneity : (i) Deviation from mirror specs (ii) Thermal effects due to circulating arm cavity power (iii) Surface roughness 3. Increase or decrease RoC of the ETM to correct for inhomogeneities (choose between the ring-heater design and the VIRGO chrocc design) |
2. Desired tuneable range and achievable range |
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| 4. Desired tuneable range and achievable range | 3. Heaters and heating patterns |
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| 5. Effect of heating at 1064nm and 532nm 6. Best heating profile 7. Practical/hardware limitations in implementing |
4. Practical/hardware limitations in implementing |
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| == Modelling using SIS/COMSOL == | == Outline == == Simulation/Modelling == 1. Find the ideal/real cavity parameters (higher order mode degeneracy) - SIS 2. Frequency tuning - SIS 3. Heating patterns - COMSOL 4. Thermally perturbed cavity analysis - SIS |
Tuning Fabry-Perot cavity modal frequencies using controlled thermoelastic deformations on mirror surface
Goal
The lessons learned from this exercise will help in designing/implementing a similar kind of system for the folding mirrors in the recycling cavities.
Fact-finding
- What are the ideal cavity parameters? (a reference to compare the different heating models)
- Desired tuneable range and achievable range
- Heaters and heating patterns
- Practical/hardware limitations in implementing
Outline
Simulation/Modelling
- Find the ideal/real cavity parameters (higher order mode degeneracy) - SIS
- Frequency tuning - SIS
- Heating patterns - COMSOL
- Thermally perturbed cavity analysis - SIS