Current Issues of the IFO design
This page summarizes the current issues of the LCGT IFO design and provides links to pages discussing the details of each problem.
Arm Cavity Parameters
Finesse
1550 is the default value decided by the IFOBW working group.
Issues
- 1550 could be too high. Need more investigations on what could go wrong.
- Mirror loss = 45ppm per reflection. Is it possible ?
- Actually, the current PRM design allows up to 65ppm without significant power loss (by Kentaro). Reference needed.
g-factor (mirror ROC)
g1 = g2 = sqrt(1/3) = 0.57735 is the conventional number to avoid HOM resonances. For L = 3000.0m, it gives ROC = 7098.08m.