= Actual Optical Parameters of the Main Interferometer =
<<TableOfContents(3)>>

== Optical Parameters ==
=== Interferometer Diagram ===
{{attachment:MIF-diagram.png|MIF Diagram|width="800"}}

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 [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=2379|CAD drawings]].

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=== 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 ||||<style="text-align:center"> ||
||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 [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=2379|CAD drawings]] ||||||<style="text-align:center"> ||


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 ||||<style="text-align:center"> ||
||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 ||||<style="text-align:center"> ||
||PRM ||4.457mm ||PR2 ||4.457mm ||PR3 ||36.639mm ||
||SRM ||4.308mm ||SR2 ||4.328mm ||SR3 ||36.666mm ||


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== 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 ||