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AUX OPTICS SUPPORTMichael Smith, 6/11/03

STRAY LIGHT CONTROL ACTIVE OPTICS COMPENSATION OUTPUT MODE CLEANER PO MIRROR AND PO TELESCOPE INITIAL ALIGNMENT SYSTEM OPTICAL LEVER SYSTEM PHOTON DRIVE

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STRAY LIGHT CONTROL

REQUIREMENT: noise < 1/10 gravity wave signal» BAFFLES

– Errant beam baffles:MC1, MC2, MC3, MMT1, MMT2, MMT3, PRM (45)– Input optics baffle: HAM2, HAM8 (3)– Recycling cavity elliptical baffles: ITMx, ITMy, PRM (9)– Arm cavity baffles: ITMx, ITMy, ETMx, ETMy (12)– ETM telescope input baffle (6)– Cryopump baffles

Manifold baffle: in manifold between cryopump and ETM (3) Conical baffle: in vertex cryopump spool (3)

» BEAM DUMPS– Ghost beam dumps in vertex area: ITMx, ITMy, BS, PRM, SRM (84)

» OUTPUT FARADAY ISOLATOR (LIGO1) (3)

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ACTIVE OPTICS COMPENSATION

See Dave Ottaway presentation

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OUTPUT MODE CLEANER

Requirements:» Transmissivity >99%» Linewidth <2 MHz FWHM

» Mode attenuation >104 for higher order modes > TEM00

Physical Characteristics» Monolithic triangular cavity, flat-flat-curved» Length approx 300 mm» Finesse > 400

Active length control-- PZT, or thermal Mode matching telescope input Video camera for auto mode identification Integrated AS photodetector

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OUTPUT MODE CLEANERCONCEPT

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PICKOFF MIRROR

• Total required, 12 (LIGO1)

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PO TELESCOPE

12:1 redux, off-axis parabolas

• Total required, 12 (LIGO1)

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INITIAL ALIGNMENT SYSTEMALIGNMENT

Requirements:» Angular pos < 0.1 mrad

» Transverse pos < 1 mm

» Axial pos < 3 mm

Equipment:» Pre-surveyed monuments

» Optical transit square

» Total station theodolite (electronic distance meas. & autocollimation)

» Lateral transfer retroreflector

» IR aucollimator/projector for alignment of PO mirrors, beam dumps, baffles, and PO telescopes

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INITIAL ALIGNMENT SYSTEMVISUALIZATION

CHAMBER ILLUMINATION CHAMBER VIDEO IMAGING

NOTE: Existing chamber illuminators and video cameras will be used

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OPTICAL LEVER SYSTEM

REQUIREMENTS» Provide continuous pitch and yaw measurement of COC orientation» Direct access to mirror surface through external viewport» Long-term stability <0.1 mrad

Physical Characteristics» Laser

– Wavelength 670-980 nm– Power TBD

» Sensor– Quad photodiode– Focal plane imaging system to sense angle only, coarse and fine zoom

sensitivity

» Total required 21

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OPTICAL LEVER FOCUS LENSCONCEPT

•Focal length zoom 6.7 – 40m

•Angle sensitivity 1 x 10-3 - 2 x 10-7 rad

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PHOTON DRIVE

REQUIREMENTS» Longitudinal force 0.1 nN» Force noise power < 2.5 x 10-15 N/Hz ½

» Dynamic range > 4 x 104 Hz ½ CHARACTERISTICS

» Laser– Wavelength 980-1047 nm– Power 1 W

» Relative intensity noise < 2 x 10-7 Hz-½ » Total required 6

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PHOTON DRIVECONCEPT