DEVELOPMENT OF FREE FALL TYPE DISPLACEMENT NOISE FREE INTERFEROMETER GRAVITATIONAL WAVE DETECTOR

Displacement-Noise-Free Interferometer for gravitational wave detector could be a breakthrough idea which can greatly exceed the sensitivity of conventional detectors by cancelling displacement noise. Furthermore, radiation pressure noise, the quantum noise, can also be canceled, which means that DFI might be able to exceed the standard quantum limit. However, displacement noises cannot be canceled completely due to the limit of the subtraction capability. In order to improve this imperfect subtraction efficiency, we use free fall type displacement-noise-free interferometer, which is free from seismic noise and thus free from mirror suspension thermal noise. In this study, we have developed a free-fall DFI as standalone system and have identified excess noises from expected sensitivity