40m Optical Systems & Sensing DRD, G R 1 40m Optical Systems and Sensing Design Requirements Document & Conceptual Design Michael Smith 10/18/01 Interferometer Input Beam Optical Sensing Beams Viewports

40m Optical Systems & Sensing DRD, G R 2 40 m IFO Vertex Section

40m Optical Systems & Sensing DRD, G R 3 40 m IFO IMC Section

40m Optical Systems & Sensing DRD, G R 4 40 m IFO End Section

40m Optical Systems & Sensing DRD, G R 5 Core Optics Parameters Physical QuantityPRMSRMBSITMETM AR 1060 nm< < AR 940 nm>0.4 NA Substrate thickness, mm28 50 Mirror power loss fraction< Mirror 1060 nm Mirror 940 nm>0.4 Mirror 670 nm>0.04 Refractive 1064 nm Beam waist, mm ppm power contour radius, mm Mirror diameter, mm Mirror thickness, mm25 50

40m Optical Systems & Sensing DRD, G R 6 Input Monitor

40m Optical Systems & Sensing DRD, G R 7 Position Sensor Response ParameterRequirementActual position ratio, mm/mm Cross coupling, mm/rad -1.07E-13 Beam displacement resolution, mm< Beam sample fraction< 1%1% sample

40m Optical Systems & Sensing DRD, G R 8 Angle Sensor Response ParameterRequirementActual Transfer ratio, mm/rad Cross coupling, rad/mm 0 Beam angular pointing resolution, rad2E-53E-6 Beam sample fraction< 1%1% sample

40m Optical Systems & Sensing DRD, G R 9 IMC Mode-matching Lenses L1L2

40m Optical Systems & Sensing DRD, G R 10 Power Coupling Error into IMC

40m Optical Systems & Sensing DRD, G R 11 Input Beam Power Control Half-wave plate Polarizer ParameterRequirementActual Wavelength1064 nm Polarizing beam splitter Extinction ratio> 100:1> 1000:1 Transmissivity> 97%> 98% Half-wave plate Type Zero order Retardation tolerance < 1% ellipticity Transmissivity > 99.7% Beam dump

40m Optical Systems & Sensing DRD, G R 12 Summary of IMC Beam Steering Performance Characteristics ParameterRequirementActual Spot IMC1.6 mm Lateral IMC+/- 1.6 mm+/- 2.9 mm Divergence angle of IMC0.21 mrad Angular tilt+/ mrad+/- 1.0 mrad Angular slew rateTBD

40m Optical Systems & Sensing DRD, G R 13 Input Mode Cleaner

40m Optical Systems & Sensing DRD, G R 14 IMC Performance Characteristics ParameterRequirementActual Plane mirror transmittance0.002 Plane mirror reflectance0.998 Curved mirror transmittance< 1 x AR coating reflectivity< 0.2 % Mirror power loss< Finesse1550 Free spectral range11.83 MHz Power build-up factor450 Transmissivity of IMC> 85 % Cavity bandwidth width/half max 7.56 kHz Cavity optical half-length12680 mm G = 1-L/R0.29 Waist size ppm diameter, curved mirror16.17 Length control, dynamic range27 micron pk-pk Angle control, dynamic range1.5 mrad pk-pk Length noise density3 x m/rtHz

40m Optical Systems & Sensing DRD, G R 15 Input Faraday Isolator ParameterRequirementActual Wavelength1064 nm Transmissivity across clear aperture > 95% Input polarization Perpendicular to optical table Output polarization Parallel to optical table Attenuation factor1000:1 Input Faraday isolator

40m Optical Systems & Sensing DRD, G R 16 IFO Mode Matching Telescope Performance Characteristics ParameterRequirementActual Clear aperture M1, mm8.819 Clear aperture M2, mm Input beam waist radius, mm 1.66 Output beam waist radius, mm Power coupling error<0.05< Wavefront distortion <0.2 Transmissivity across clear aperture > 99.8%, ion beam coating Magnification1.8 PZT steering mirror

40m Optical Systems & Sensing DRD, G R 17 IFO Beam Steering Performance Characteristics Position Steering Angle steering ParameterRequirementActual Spot size of IFO beam3.03 mm Position steering+/-3.03 mm+/- 4 mm Divergence angle of IFO beam rad Angular steering rad+/ rad Resonant frequency 3500 Hz Angle sensing Internal strain gage PRM

40m Optical Systems & Sensing DRD, G R 18 Initial Pointing Beam Angle Sensor ParameterRequirementActual Pointing angleSame as IFO beam Angle resolution rad< rad Sensor bandwidth > 100 kHz Main beam sample fraction< 1 %0.25 % ETM

40m Optical Systems & Sensing DRD, G R 19 IMC Reflected Beam System

40m Optical Systems & Sensing DRD, G R 20 IMC Reflected Beam Performance Characteristics ParameterRequirementActual Wavefront distortion< nm< nm Main beam sample fraction 0.6 % WFS1, Guoy phase 1Quad photodiode, 29.5 MHz WFS2, Guoy phase 2Quad photodiode, 29.5 MHz LS, RF photodiode29.5 MHz Fast beam shutterYesEO shutter Mechanical beam blockYesUniblitz Video cameraYesWatek Reflected power monitorYes

40m Optical Systems & Sensing DRD, G R 21 IMC Transmitted Beam Performance Characteristics Mechanical beam-block Spectrum analyzer Power photodiode Video camera ParameterRequirementActual Wavefront distortion< nm < nm Main beam sample fraction0.6 % RFAM RF photodetectorTBD PSL intensity stabilization, RF photodetector TBD Transmitted power photodetector Yes Optical Spectrum analyzerYesCoherent Fast beam shutterYesEO shutter Mechanical beam blockYesUniblitz Video camerayesWatek

40m Optical Systems & Sensing DRD, G R 22 SPS Sensing System Spectrum analyzer Power monitor Video camera EO shutter Mechanical shutter Bull’s eye detector

40m Optical Systems & Sensing DRD, G R 23 Symmetric Port Signal Performance Characteristics ParameterRequirementActual Wavefront distortion< nm< nm Symmetric port power ratio0.01 WFSP-2, frequencyQuad photodiode, TBD MHz LSSP-1, frequency35.5 MHz LSSP-2, frequency141.9 MHz Bull’s eye photodetector TBD Fast beam shutterYesEO shutter Mechanical beam blockYesUniblitz

40m Optical Systems & Sensing DRD, G R 24 ITMx, ITMy pick-off beam ITM

40m Optical Systems & Sensing DRD, G R 25 BS Pick-off Beam BS ITM

40m Optical Systems & Sensing DRD, G R 26 ITM Pick-off Beam Sensing System Spectrum analyzer Power monitor Video camera Mechanical shutter

40m Optical Systems & Sensing DRD, G R 27 BS Pick-off Beam Sensing System Spectrum analyzer Power monitor Video camera Mechanical shutter ParameterRequirementActual Wavefront distortion< nm < nm Pick-off power ratio WFSPPR, Guoy phase 1 Quad photodiode, MHz WFSPPR, Guoy phase 2 Quad photodiode, MHz LSSPRP-1, frequency141.9 MHz

40m Optical Systems & Sensing DRD, G R 28 Output Faraday Isolator Characteristics ParameterRequirementActual Wavelength1064 nm Transmissivity across clear aperture > 95% Extinction ratio1000:1 Clear aperture13 mm20 mm Faraday material TGG BS SRM Faraday

40m Optical Systems & Sensing DRD, G R 29 AP1 ISC System Spectrum analyzer Video camera Mechanical shutter EO shutter Power monitor

40m Optical Systems & Sensing DRD, G R 30 AP1 ISC System Performance Characteristics ParameterRequirementActual Wavefront distortion< nm< nm Output power ratio0.01 WFAP-1, Guoy phase 1Quad photodiode, TBD MHz WFAP-2, Guoy phase 2Quad photodiode, TBD MHz LSAP-1, frequency177.3 MHz LSAP-2, double demodulation141.9 MHz, MHz35.5 MHz Fast beam shutter yesEO shutter Mechanical beam block yes Uniblitz Video camera Watek Optical spectrum analyzer Coherent

40m Optical Systems & Sensing DRD, G R 31 OMC Reflected Beam Sensing System ParameterRequirementActual Wavefront distortion< nm < nm Main beam sample fraction0.01 WFS1, Guoy phase 1Quad photodiode, MHz QPD, MHz WFS2, Guoy phase 2Quad photodiode, MHz QPD, MHz LS, RF photodiode177.3 MHz Fast beam shutterYesEO shutter Mechanical beam blockYesUniblitz Video cameraYesWatek Reflected power monitor photodiode yes Video camera Mechanical shutter EO shutter Power monitor

40m Optical Systems & Sensing DRD, G R 32 ETM Transmission Monitor Video camera attenuator ETM ParameterRequirementActual Output power ratio0.01 Position transfer ratio, mm/mm Beam position pointing resolution, mm Beam splitter attenuation ratio0.1

40m Optical Systems & Sensing DRD, G R 33 OMC Mode Matching Telescope ParameterRequirementActual Clear aperture M1, mm1325 Clear aperture M2, mm319 Input beam waist radius, mm3.027 Output beam waist radius, mm Power coupling error<0.05< Wavefront distortion <0.2 Transmissivity across clear aperture > 99.8%, ion beam coating Magnification0.23

40m Optical Systems & Sensing DRD, G R 34 OMC Beam Steering ParameterRequirementActual Spot size of OMC beam0.37 mm Position steering+/-0.37 mm+/- 0.8 mm Divergence angle of OMC beam rad Angular steering rad+/ rad Resonant frequency 3500 Hz Angle sensing Internal strain gage

40m Optical Systems & Sensing DRD, G R 35 AP2 ISC Optical Train ParameterRequirementActual AP2 power ratio0.005 GWS photodetector frequency responseDC - 10 KHz Seismic velocity of GWS photodetectorTBD Video camera power sensor EO shutter

40m Optical Systems & Sensing DRD, G R 36 Viewports, Types and Locations LocationType Ouput-chamber, 1Optical quality, type 1 Ouput-chamber, 2Optical quality, type 1 Ouput-chamber, 3Optical quality, type 1 Input chamber, “T”Camera Input chamber, topCamera Mode cleaner chamberCamera BS chamberOptical quality, type 2 East vertex chamber, midOptical quality, type 2 East vertex chamber, upperCamera South vertex chamber, midOptical quality, type 2 South vertex chamber, upperCamera East end chamber, midOptical quality, type 2 East end chamber, upperCamera South end chamber, midOptical quality, type 2 South end chamber, upperCamera

40m Optical Systems & Sensing DRD, G R 37 Tilted Viewport ParameterRequirementActual Tilt angle2.5 deg Scattering BRDF, sr -1 < 0.04TBD Reflectivity 1064 nm, normal incidence < 0.1 % Reflectivity nm, normal incidence < 0.75 %