1. G030275-00-Z LIGO R&D1 Input Optics Definition, Function The input optics (IO) conditions light from the pre- stabilized laser (PSL) for injection into the main interferometer Specific functions »modulation for RF sideband generation »Mode cleaning of dynamic laser pointing fluctuations; intermediate frequency and intensity stabilization »Power control into interferometer »Mode matching into interferometer cavities »Optical isolation of the PSL and distribution of light for length and alignment sensing and control

2. G030275-00-Z LIGO R&D2 Input Optics Conceptual Design

3. G030275-00-Z LIGO R&D3 Input optics heritage Advanced LIGO IO evolves from current LIGO IO »No major changes in AdL IO conceptual design Contiguity of IO team from current LIGO IO »Univ. of Florida assumes primary responsibility (as in current LIGO) »IO technical leaders same as in LIGO In terms of R&D, most progressed of Advanced LIGO subsystems »Relatively low technical risk »Conceptual Design and Design Requirements completed May 2002 Major R&D »Electro-optic modulators: materials, architecture »Faraday Isolators: thermal lensing, depolarization, dynamics »Adaptive mode matching »Mode cleaner thermal and noise modeling

4. G030275-00-Z LIGO R&D4 Isolators »Demonstration of fully compensated TGG-based isolator »45 dB isolation »Negligible thermal lensing Modulators »RTP: excellent thermal properties and nonlinear properties »RTP-based transverse modulator prototype tested –temperature-stabilized –no thermal lensing observed at 50 W powers Current Progress I No thermal compensation Thermal compensation

5. G030275-00-Z LIGO R&D5 Current Progress II Adaptive Mode Matching »in situ adjustment of mode matched based on laser/radiative heating »Ratio of ‘writing’ beam to ‘reading’ beam waist large »Preserves modal content Model Performance 1064 nm 532 nm Schott OG515 Preliminary Experiment

6. G030275-00-Z LIGO R&D6 Technical Challenges/Opportunities Challenges: »High power poses problems to IO optical components –Thermal lensing, thermally-induced depolarization, long term degradation –Primarily affects electro-optic modulators –Sideband amplitude stability –challenging for DC readout; beyond state-of-the-art for RF oscillators »Excess laser jitter may require active suppression –MC technical radiation pressure at requirement limit for required frequency noise Opportunities »Novel adaptive optics

7. G030275-00-Z LIGO R&D7 R&D Plans for 2004 Upgrade to 100 W laser testing »LIGO Livingston High Power Test Lab (underway) EOM prototype testing »RF amplitude modulation, amplitude modulation from parasitic nonlinear processes »Frequency stability (at limit of RF oscillator) »Long term laser exposure and damage testing (100 W powers) »Contingency modulation architectures if required Mode cleaner R&D »MELODY model of thermal effects (carrier, sidebands), potential astigmatism (mostly done) »Better understanding of beam jitter in PSL; if necessary, examination of possibility of second mode cleaner

8. G030275-00-Z LIGO R&D8 R&D Plans for 2004 (cont’d) Faraday isolation »Investigate dynamic effects due to loss of lock and rapid thermal loading »Trade study of optimal commercial components (wave plates, polarizers, TGG) Interferometer mode-matching »Prototype thermal adaptive telescope in vacuum »Preliminary Advanced LIGO telescope design; MELODY modeling of performance under various powers System interface issues »In-vacuum layout (underway)

9. G030275-00-Z LIGO R&D9 Schedule Design phase »Design Requirements and Conceptual Design: May 2002 (completed) »Preliminary Design Phase: April 2005 »Final Design: November 2007 »Milestones –Design LASTI mode cleaner and ancillary input optics: November 2002 (completed) –Deliver prototype modulators and isolators to Gingin High Power Test Facility: June 2004 –Deliver LASTI mode cleaner and ancillary optics: January 2005 –Deliver prototype modulators and isolators to LASTI: January 2006 Fabrication and assembly phase »Major optics procurement (all interferometers): August 2006 – August 2009 »Input optics installation –Interferometer 1: thru August 2008 –Interferometer 2: thru February 2009 –Interferometer 3: thru September 2009

10. G030275-00-Z LIGO R&D10 IO Team IO Manager: D. Reitze (Univ. Florida) LIGO Lab Liaison: P. King (CIT) IO Team »Univ. of Florida –R. Amin, K. Franzen, G. Mueller, M. Rakhmanov, D. Tanner, V. Quetschke, L. Zhang » Institute of Applied Physics (Nizhny Novgorod, Russia) –E. Khazanov, A. Malshakov, A. Shakin, A. Sergeev »LIGO Lab –P. King, R. Savage