1 / 14

K.Somiya

Ponderomotive amplifier to reduce shot noise. GWADW @ Kyoto May. 2010 Kentaro Somiya 1 and Yanbei Chen 2 Waseda Inst. for Adv. Study 1 and Caltech 2. K.Somiya. High-freq sensitivity of GWD. reso. reso. High Finesse. RSE. PRM. anti-reso. SRM.

ethan
Download Presentation

K.Somiya

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ponderomotive amplifier to reduce shot noise GWADW @ Kyoto May. 2010 Kentaro Somiya1 and Yanbei Chen2 Waseda Inst. for Adv. Study1 and Caltech2 K.Somiya

  2. High-freq sensitivity of GWD reso reso High Finesse RSE PRM anti-reso SRM SR gain could be higher if the arms were shorter. Optical-bar regime by Braginsky and Khalili

  3. Optical-bar regime [Braginsky 98] [Rehbein 07] locked by opt spring interpretation ITM ETM local-readout (high SRG) local-readout • Dual Recycling instead of PR+RSE (f<spring) • Signal enhancement at spring frequency • High power required to increase spring frequency

  4. Optical lever [Khalili 02] [Danilishin 06] [Chen 03] 40kg 1g 4km interpretation 1m more signal less power free locked Ponderomotive amplifier • Reasonable power on the small mirrors • Chen-type optical lever is rather an amplifier • GW signal converts to radiation pressure in PA

  5. Ponderomotive amplifier 40kg GW signal 4km 1g 1m coupled with pump sig (phase) sig (phase) sig (amp) RP sig (phase) RP sig (amp) pump (amp) carrier (amp) RP signal reenters • Vacuum enters from the pick-off • Optimized combination of the • two outputs in the best quadrature coupled with carrier

  6. … … A= B= input coupler Ponderomotive amplifier B Amp maximize SNR I1x … + I2x … + … I1 I2 GWD A I2x[vacuum + signal + disp-noise] q: detune phase T: transmittance of input coupler If I2-term is dominant… 4Tcosq I1(1-T) Shot noise Signal Signal is amplified and SNR increases

  7. Sensitivity gain GWD L=4km, m=40kg, I0=1kW, F=120 PA L=10cm, m=1g, I0=100W, F=6000 IC R=81%, f=1.5rad • Big reduction of shot noise up to kHz • Strong against PD losses • Power on PA might be a bit high…

  8. PA displacement noise • The small-mirror IFO will be noisy • The motion is suppressed by the optical spring

  9. Sensitivity curve • Not yet fully optimized • Good sensitivity with low power • PA noise limits the sensitivity at high freq

  10. Single-path ponderomotive amplifier PBS (TF and QN of DRSE) Amp I1 I2 GWD vacuum • It turns out this one doesn’t work • Signal and noise increases at once • Recall the situation with detuned RSE…

  11. Summary • Ponderomotive amplifier based on optical lever • Reduction of shot noise • Strong against optical losses • PA displacement noise is suppressed by spring • Possible combinations: • LIGO + MIT 1g IFO • Virgo + LKB micro-mirror • GEO + membrane • TAMA + NAO 20mg IFO… etc.

  12. End

  13. Transfer function of signal/noise

More Related