Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Demonstration of lock acquisition and optical response on Detuned RSE interferometer at Caltech 40m GWADW-VESF meeting @ Elba May 31, 2006 Osamu Miyakawa, Caltech + 40m team LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 1 Advanced LIGO optical configuration LIGO:Power recycled FPMI » Optical noise is limited by Standard Quantum Limit (SQL) FP cavity AdvLIGO:GW signal enhancement using Detuned RSE » Two dips by optical spring, optical resonance » Can overcome the SQL QND detector Laser PRM Power FP cavity BS GW signal Detuning SRM LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 2 Historical review of Advanced interferometer configuration ~1986 Signal Recycling (Dual Recycling) [B.Meers] ~1998 Garching 30m [G.Heinzel] GEO600 Glassgow 10m ~1993 RSE •Idea [J.Mizuno] •Tabletop [G.Heinzel] ~2000 Tabletop with new control • Caltech(RSE)[J.Mason] • Florida(DR) • Australia(RSE)[D.Shaddock] ~2002 NAOJ 4m Susp. mass BRSE(No PR) [O.Miyakawa] ~2005 Caltech 40m • Suspended mass • DRSE+PR ~2013 AdLIGO(DRSE) LCGT(BRSE) AdVIRGO ~2004 NAOJ 4m Susp. mass DRSE(No PR) [K.Somiya] ~2001 QND study[Y.Chen, A. Buonanno] •Optical spring •Readout scheme LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 3 Caltech 40 meter prototype interferometer An interferometer as close as possible to the Advanced LIGO optical configuration and control system Detuned Resonant PRM Sideband Extraction(DRSE) Power Recycling Suspended mass Bright Digital controls system port To verify optical spring and optical resonance To develop DC readout scheme To extrapolate to AdLIGO via simulation BS SRM Dark port X arm Y arm LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 4 Signal extraction scheme ETMy 4km f2 ITMy PRM BS ITMx ETMx Mach-Zehnder is installed to eliminate sidebands of sidebands. Only + f2 is resonant on SRC. Unbalanced sidebands of +/-f2 due to detuned SRC produce good error signal for Central part. 4km f1 SRM -f2 Carrier (Resonant on arms) • Single demodulation • Arm information -f1 f1 f2 • Double demodulation • Central part information Arm cavity signals are extracted from beat between carrier and f1 or f2. Central part (Michelson, PRC, SRC) signals are extracted from beat between f1 and f2, not including arm cavity information. LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 5 Mach-Zehnder interferometer to eliminate sidebands of sidebands Series EOMs with sidebands of sidebands f1 Mach-Zehnder interferometer with no sidebands of sidebands PMC trans f2 f2 PZT Carrier EOM1 EOM2 Locked by internal modulation Carrier EOM2 f1 -f2 -f1 f1=33MHz f2=166MHz 133MHz 199MHz To MC -f2 -f1 f2 f1 EOM1 PD PMC transmitted to MC LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 6 Pre-Stabilized Laser(PSL) and 13m Mode Cleaner(MC) BS East Arm ITMx ITMy Mode Cleaner South Arm PSL ETMx MZ PMC MOPA126 FSS ISS Detection bench ETMy LIGO- G060231-00-R 10W MOPA126 Frequency Stabilization Servo (FSS) Pre-Mode Cleaner (PMC) Intensity Stabilization Servo(ISS) 13m suspended-mass Mode Cleaner GWAWD-VESF meeting at Elba, May 2006 7 LIGO-I type single suspension Each optic has five OSEMs (magnet and coil assemblies), four on the back, one on the side The magnet occludes light from the LED, giving position Current through the coil creates a magnetic field, allowing mirror control LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 8 The way to full RSE Detuned dual recycled Michelson 5 DOF lock with offset in CARM ETMy RSE Reducing CARM offset ITMy PRM BS ITMx ETMx SRM Carrier 33MHz 166MHz LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 9 Lock acquisition procedure towards detuned RSE Low gain High gain TrY PDs POY ITMy 166MHz POX 13m MC BS ITMx High gain 33MHz PRM SP33 PO DDM SRM SP166 TrX PDs Low gain SP DDM AP166 AP DDM LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 10 Lock acquisition procedure towards detuned RSE Low gain DRMI + 2arms with offset using DRMI digitally normalized 1/sqrt(TrY) High gain Normalization process OSA@SP Carrier TrY PDs 1 offset Transmitte d power Unbalanced 166MHz 1. Avoids coupling of carrier in PRC 2. Lock with low bandwidth control 3. High cavity pole 33MHz POY ITMy 166MHz Belongs to next carrier POX 13m MC BS Resonant Off-resonant Lock Lock point ITMx Belongs to next carrier OSA@AP 1/sqrt(TrX) High gain 33MHz PRM SP33 Q SP166 I SP DDM PO DDM SRM TrX PDs Low gain AP166 AP DDM LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 11 Belongs to next carrier Lock acquisition procedure towards detuned RSE 1/sqrt(TrY) Low gain DRMI + 2arms with offset using digitally normalized Normalization process High gain TrY PDs 1 offset Transmitte d power 1. Avoids coupling of carrier in PRC 2. Lock with low bandwidth control 3. High cavity pole Resonant Off-resonant Lock Lock point Ly=38.55m Finesse=1235 POY ITMy 166MHz POX 13m MC 33MHz BS ITMx Lx =38.55m Finesse=1235 PRM T =7% SP33 SP166 I SP DDM Q 1/sqrt(TrX) SRM T =7% PO DDM High gain TrX PDs Low gain AP166 AP DDM LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 12 Lock acquisition procedure towards detuned RSE Low gain Short DOFs -> DDM CARM-> Normalized RF DARM->Normalized RF TrY PDs Design RSE peak ~ 4kHz Ly=38.55m Finesse=1235 + + CARM with offset DARM with no offset Normalization process High gain POX/TrX+POY/TrY POY ITMy 166MHz + CARM -1 DARM + POX 13m MC 33MHz BS ITMx Lx =38.55m Finesse=1235 PRM T =7% SP33 SP166 SP DDM High gain SRM T =7% PO DDM TrX PDs Low gain AP166 AP DDM LIGO- G060231-00-R AP166/(TrX+TrY) GWAWD-VESF meeting at Elba, May 2006 13 Lock acquisition procedure towards detuned RSE Low gain TrY PDs Reduce CARM offset to Full RSE Ly=38.55m Finesse=1235 + + 166MHz 33MHz POX/TrX+POY/TrY + ITMy 13m MC Normalization process High gain CARM -1 POX GPR=14.5 BS ITMx High gain Lx =38.55m Finesse=1235 PRM T =7% SP33 SP166 SP DDM DARM + SRM T =7% PO DDM TrX PDs Low gain AP166 AP DDM LIGO- G060231-00-R AP166/(TrX+TrY) GWAWD-VESF meeting at Elba, May 2006 14 DARM Optical response with fit to A.Buonanno & Y.Chen formula 40m DARM Optical Response Radiation pressure:F = 2 P / c Detuned Cavity -> dF/dx Optical Spring stiffness ~107 N/m dB mag (arb units) Optical spring and optical resonance of detuned RSE were measured and fitted to ABYC formula. 440 430 420 410 400 390 B&C Data 380 370 1 10 BMW Z4 ~ 104 N/m 4 3 2 10 10 10 Phase (deg) 200 100 0 -100 -200 1 10 4 3 2 10 10 10 f (Hz) Description of data, fit: http://arxiv.org/abs/gr-qc/0604078 LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 15 Mathematical description for optical spring in detuned RSE ABYC equation:relation using two photon mode among input vacuum a , output field b, input power and gravitational wave h D b1 1 2i C11 C12 a1 i 1 h e 2 e D h b2 M C21 C22 a2 2 SQL hSQL:standard quantum limit t: transmissivity of SRM k: input power coupling b: GW sideband phase shift in IFO Strain sensitivity: ratio h and a on b hSQL (C11 C22 ) 2 sin (C12 C21 ) 2 cos i e hn ( ) D1 sin D2 cos 2 Optical noise: ratio between a and b b (C11 C22 ) 2 sin (C12 C21 ) 2 cos a M arm cavity a :input vacuum b :output field M2: C11C22-C12C21 h :gravitational wave h h arm cavity laser ei 2 Signal recycling mirror a b Measurement of optical response: ratio h and b b h 2 D1 sin D2 cos i e hSQL M LIGO- G060231-00-R a <<h; non-quantum measurement GWAWD-VESF meeting at Elba, May 2006 16 Simple picture of optical spring in detuned RSE Let’s move arm differentially, X arm longer, Y arm shorter from full RSE Wrong SRM position Correct SRM position BRSE Power(W) Power(W) X arm X arm Y arm Power(W) Y arm DARM (Lx-Ly) DARM (Lx-Ly) Power X arm down, Y arm up Radiation pressure X arm down, Y arm up Spring constant Positive (optical spring) LIGO- G060231-00-R DARM (Lx-Ly) X arm down, Y arm down X arm up, Y arm down X arm down, Y arm down X arm up, Y arm down N/A Negative (no optical spring) GWAWD-VESF meeting at Elba, May 2006 17 Frequency sweep of optical spring ~1900W ~270W LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 18 CARM optical resonance and Dynamic compensative filter Open loop TF of CARM Optical gain of CARM • Optical gain (normalized by transmitted power) shows moving peaks due to reducing CARM offset. • We have a dynamic compensative filter having an exactly the same shape as optical gain except for upside down. • Open loop transfer function has no phase delay in all CARM offset. LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 19 CARM optical springs CARM optical springs at different CARM offsets 140 Arm power = 6 Arm power = 8 Arm power = 10 •Solid lines are from TCST •Stars are 40m data •Max Arm Power is ~80 130 CARM optical response (dB) 120 110 100 90 80 2 3 10 10 f (Hz) LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 20 GW readout, Systems DC rather than RF for GW sensing » Requires Output Mode-Cleaner to reject RF » Offset ~ 1 picometer from dark fringe can tune from 0 to 80 deg with 0-100 mW of fringe offset power Noise Source Laser frequency noise Laser amplitude noise RF readout DC readout ~10x more sensitive Less sensitive since carrier is filtered Sensitivity identical for frequencies below ~100 Hz; both driven by technical radiation pressure 10-100x more sensitive above 100Hz Carrier is filtered Laser pointing noise Sensitivity essentially the same Oscillator phase noise -140 dBc/rtHz at 100 Hz LIGO- G060231-00-R fringe offset β Loss mismatch Mode matching telescope OMC DC PD NA GWAWD-VESF meeting at Elba, May 2006 21 Squeezing Tests at the 40m Go from MIT group brought an audio frequency squeezer to 40m, and injection of squeezed vacuum will be tested. SHG, OPO ready, homodyne detector being developed. Time to take steps toward injection to 40m interferometer » DRSE configuration will be tested » LIGO-like control systems for eventually porting squeezing technology to long baseline ifos SHG 2W from MOPA Squeezed vacuum to IFO OPO LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 22 Other ideas Low frequency-low frequency RF modulation scheme (40m:33-55MHz, AdLIGO:27-45MHz) instead of LF-HF RF Alignment Sensing and Control (ASC) on detuned RSE with LF-LF RF modulation ASC with lighter mirrors in order to investigate pitch and yaw optical springs Variable band operation using SRC error signal normalized by LF f2 power LIGO- G060231-00-R GWAWD-VESF meeting at Elba, May 2006 23