Actual Optical Parameters of the Main Interferometer
Contents
Optical Parameters
Interferometer Diagram
Note: In this figure POP is taken at the transmission of PR3, because it is easier to draw. In reality, POP will be taken at the transmission of PR2 (beam from PR3 to PR2).
For more accurate optical layout, please refer to the CAD drawings.
ITM=1.9km, ETM=1.9km, PRC=16.5deg, SRC=17.5deg, 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 |
14.7615 |
Lp2 |
11.0661m |
Lp3 |
15.7638m |
Lmi |
25m |
Lmx |
26.6649m |
Lmy |
23.3351m |
Ls1 |
14.7412m |
Ls2 |
11.1115m |
Ls3 |
15.7386m |
Folding Angle |
Different for different mirrors. |
See the CAD drawings |
|
||
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 |
1900.0m |
ETM |
1900.0m |
|
|
PRM |
458.1285m |
PR2 |
-3.0764m |
PR3 |
24.9165m |
SRM |
458.1285m |
SR2 |
-2.9872m |
SR3 |
24.9165m |
Beam Spot Size (1/e^2 radius)
ITM |
35.3mm |
ETM |
35.3mm |
|
|
PRM |
4.457mm |
PR2 |
4.457mm |
PR3 |
36.639mm |
SRM |
4.308mm |
SR2 |
4.328mm |
SR3 |
36.666mm |
Mirror Specs
See, also, http://gwwiki.icrr.u-tokyo.ac.jp/optics/database.cgi .
Test Masses
ITM
Diameter |
220mm |
|
Thickness |
150mm |
|
HR Radius of Curvature |
1.90(+/-0.0095)km |
0.5% error |
AR Radius of Curvature |
Flat (>100km) |
As flat as possible |
AR Wedge Angle |
0.025+0/-0.002deg |
Wedge direction: seen from the HR surface, 9 o'clock is thickest for both ITMX and ITMY. |
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 |
HR Loss@1064nm |
<45ppm |
|
Transmission@532nm |
0.06(+0/-0.005) |
Transmission of ITM must be larger than ETM@532nm |
Transmission asymmetry@532nm |
No requirement |
|
HR Loss@532nm |
<1% |
|
AR Reflectivity@1064nm |
200(+100/-0)ppm |
|
AR Reflectivity@532nm |
<5% |
As small as possible |
ETM
Diameter |
220mm |
|
Thickness |
150mm |
|
HR Radius of Curvature |
1.9(+/-0.0095)km |
0.5% error |
AR Radius of Curvature |
Flat (>100km) |
As flat as possible |
AR Wedge Angle |
0.05+/-0.01deg |
Wedge direction: Seen from the HR surface, 3 o'clock is thickest for ETMX, 9 o'clock is thickest for ETMY. |
Transmission@1064nm |
5ppm < T < 10ppm |
|
Transmission asymmetry@1064nm |
2*|(T1-T2)/(T1+T2)| < 0.01 |
Best Effort |
HR Loss@1064nm |
<45ppm |
|
Transmission@532nm |
0.06(+0/-0.005) |
Transmission of ETM must be smaller than ITM@532nm |
Transmission asymmetry@532nm |
No requirement |
|
HR Loss@532nm |
<1% |
|
AR Reflectivity@1064nm |
<50ppm |
|
AR Reflectivity@532nm |
<5% |
As small as possible |
BS
Diameter |
370mm +/- 0.25mm |
|
Thickness |
80mm +/- 0.5mm |
|
HR Radius of Curvature |
Flat (>500km) |
As flat as possible |
AR Radius of Curvature |
Flat (>500km) |
As flat as possible |
AR Wedge Angle |
0.08+0/-0.01deg |
|
Incident Angle |
44.9684deg +/-0.05deg |
|
Transmission@1064nm |
50% +/-1% |
|
HR Loss@1064nm |
<100ppm |
|
Transmission@532nm |
>0.9 |
(99.40% for s-pol, 97.85% for p-pol designed) |
HR Loss@532nm |
<1% |
|
AR Reflectivity@1064nm |
<50ppm |
|
AR Reflectivity@532nm |
<5% |
As small as possible |
PRM
Diameter |
250mm |
|
Thickness |
100mm |
|
HR Radius of Curvature |
458.1285m(+/-20)m |
5% error |
AR Radius of Curvature |
Flat (>100km) |
As flat as possible |
AR Wedge Angle |
1.999 deg |
measured |
Transmission@1064nm |
0.1(+0.001/-0.0) |
measured to be 0.1035 |
HR Loss@1064nm |
<45ppm |
|
AR Reflectivity@1064nm |
<50ppm |
|
PR2
Diameter |
250mm |
|
Thickness |
100mm |
|
HR Radius of Curvature |
-3.0764(+/-0.01)m |
|
AR Radius of Curvature |
Flat (>100km) |
As flat as possible |
AR Wedge Angle |
2.042 deg |
measured |
Transmission@1064nm |
500ppm(+/-50ppm) |
|
HR Loss@1064nm |
<45ppm |
|
Transmission@532nm |
> 0.5 |
As large as possible (0.9 measured with witness sample at 0deg) |
HR Loss@532nm |
<10% |
|
AR Reflectivity@1064nm |
<1000ppm |
As small as possible |
AR Reflectivity@532nm |
<5% |
As small as possible |
PR3
Diameter |
250mm |
|
Thickness |
100mm |
|
HR Radius of Curvature |
24.9165(+/-0.01)m |
|
AR Radius of Curvature |
Flat (>100km) |
As flat as possible |
AR Wedge Angle |
2.019 deg |
measured |
Transmission@1064nm |
<50ppm |
As small as possible |
HR Loss@1064nm |
<45ppm |
|
Transmission@532nm |
< 0.1 |
As small as possible |
HR Loss@532nm |
<10% |
|
AR Reflectivity@1064nm |
<1000ppm |
As small as possible |
AR Reflectivity@532nm |
<5% |
As small as possible |
SRM
Diameter |
250mm |
|
Thickness |
100mm |
|
HR Radius of Curvature |
458.1285m(+/-20)m |
5% error |
AR Radius of Curvature |
Flat (>100km) |
As flat as possible |
AR Wedge Angle |
1.997 deg |
measured |
Transmission@1064nm |
0.1536(+/-0.001) |
|
HR Loss@1064nm |
<45ppm |
|
AR Reflectivity@1064nm |
<50ppm |
|
SR2
Diameter |
250mm |
|
Thickness |
100mm |
|
HR Radius of Curvature |
-2.9872(+/-0.01)m |
|
AR Radius of Curvature |
Flat (>100km) |
As flat as possible |
AR Wedge Angle |
2.096 deg |
measured |
Transmission@1064nm |
500ppm(+/-50ppm) |
|
HR Loss@1064nm |
<45ppm |
|
Transmission@532nm |
> 0.5 |
As large as possible (0.9 measured with witness sample at 0deg) |
HR Loss@532nm |
<10% |
|
AR Reflectivity@1064nm |
<1000ppm |
As small as possible |
AR Reflectivity@532nm |
<5% |
As small as possible |
SR3
Diameter |
250mm |
|
Thickness |
100mm |
|
HR Radius of Curvature |
24.9165(+/-0.01)m |
|
AR Radius of Curvature |
Flat (>100km) |
As flat as possible |
AR Wedge Angle |
2.026 deg |
measured |
Transmission@1064nm |
<50ppm |
As small as possible |
HR Loss@1064nm |
<45ppm |
|
Transmission@532nm |
< 0.1 |
As small as possible |
HR Loss@532nm |
<10% |
|
AR Reflectivity@1064nm |
<1000ppm |
As small as possible |
AR Reflectivity@532nm |
<5% |
As small as possible |