Actual Optical Parameters of the Main Interferometer
Contents
Optical Parameters
Interferometer Diagram
g1>0.994, g2=0.571, 16.875MHz, 45MHz
This is the parameter set chosen by the MIF group.
Lengths & Frequencies
f1 |
16.880962MHz (3*f2/8) |
f2 |
45.015898MHz |
f3 |
56.269873MHz (10*f2/8) |
Larm |
3000.0m |
Lmc |
26.639m |
||
Lprc |
66.591m |
Lsrc |
66.591m |
Las |
3.3299m |
Lp1 |
14.7609 |
Lp2 |
12.0667m |
Lp3 |
14.7638m |
Lmi |
25m |
Lmx |
26.6649m |
Lmy |
23.3351m |
Ls1 |
14.7609m |
Ls2 |
12.0667m |
Ls3 |
14.7638m |
Folding angle |
0.6292[deg] |
||||
Folding angle is an incident angle of the beam to the folding mirrors. The angle between incoming and reflected beams is twice the folding angle.
Radius of Curvatures (Positive for concave)
ITM |
>500km |
ETM |
7000.0m |
||
PRM |
332.28m |
PR2 |
-3.269m |
PR3 |
27.38m |
SRM |
332.28m |
SR2 |
-3.269m |
SR3 |
27.38m |
Beam Spot Size (1/e^2 radius)
ITM |
3.43cm |
ETM |
4.53cm |
||
PRM |
4.05mm |
PR2 |
4.06mm |
PR3 |
34.25mm |
SRM |
4.05mm |
SR2 |
4.06mm |
SR3 |
34.25mm |
Lens effect (effective focal length seen from the AR side)
ITM (Sapphire) |
>666km |
PRM (Silica) |
>10000km |
g1=g2=0.586, 11.25MHz, 45MHz
This is an alternative parameter set. Do not use these parameters.
Lengths & Frequencies
f1 |
11.255822MHz |
f2 |
45.023289MHz |
f3 |
39.395378MHz |
Larm |
3000.0m |
Lmc |
26.634m |
||
Lprc |
73.24838m |
Lsrc |
73.24838m |
Las |
3.3293m |
Lp1 |
16.9798m |
Lp2 |
14.2858m |
Lp3 |
16.9828m |
Lmi |
25m |
Lmx |
26.66465m |
Lmy |
23.33535m |
Ls1 |
16.9798m |
Ls2 |
14.2858m |
Ls3 |
16.9828m |
Radius of Curvatures (Positive for concave)
ITM |
7246.3768m |
ETM |
7246.3768m |
||
PRM |
361.552m |
PR2 |
-3.985m |
PR3 |
32.4m |
SRM |
361.552m |
SR2 |
-3.985m |
SR3 |
32.4m |
Beam Spot Size (1/e^2 radius)
PRM |
4.355mm |
PR2 |
4.355mm |
PR3 |
35.77mm |
SRM |
4.355mm |
SR2 |
4.355mm |
SR3 |
35.77mm |
Lens effect (effective focal length seen from the AR side)
ITM (Sapphire) |
-9610m |
PRM (Silica) |
-765.6m |
Mirror Specs
Test Masses
ITM
HR Radius of Curvature |
1.68(+/-0.008)km |
0.5% error |
AR Radius of Curvature |
Flat (>100km) |
As flat as possible |
AR Wedge Angle |
0.2+/-0.002deg |
|
Transmission@1064nm |
0.004 +0.001/-0.0 |
|
Transmission asymmetry@1064nm |
2*|(T1-T2)/(T1+T2)| < 0.01 |
T1 and T2 are the transmission of two ITMs |
Reflection Loss@1064nm |
<45ppm |
|
Transmission@532nm |
0.2(+/-0.1) |
Transmission of ITM must be larger than ETM@532nm |
Transmission asymmetry@532nm |
No requirement |
|
Reflection loss@532nm |
<1% |
|
AR Reflectivity@1064nm |
200(+100/-0)ppm |
|
AR Reflectivity@532nm |
<5% |
As small as possible |
ETM
HR Radius of Curvature |
1.87(+/-0.009)km |
0.5% error |
AR Radius of Curvature |
Flat (>100km) |
As flat as possible |
AR Wedge Angle |
0.2+/-0.1deg |
|
Transmission@1064nm |
5ppm < T < 10ppm |
|
Transmission asymmetry@1064nm |
2*|(T1-T2)/(T1+T2)| < 0.01 |
Best Effort |
Reflection Loss@1064nm |
<45ppm |
|
Transmission@532nm |
0.2(+/-0.01) |
Transmission of ETM must be smaller than ITM@532nm |
Transmission asymmetry@532nm |
No requirement |
|
Reflection loss@532nm |
<1% |
|
AR Reflectivity@1064nm |
200(+100/-0)ppm |
|
AR Reflectivity@532nm |
<5% |
As small as possible |