@misc{oai:ir.soken.ac.jp:00000383,
 author = {佐藤, 修一 and サトウ, シュウイチ and SATO, Shuichi},
 month = {2016-02-17, 2016-02-17},
 note = {Several ground-based large-scale and medium-scale laser interferometers (LIGO, VIRGO, GEO600 and TAMA300) are now under construction for gravitational wave detection. A power-recycling technique is planned as a standard optical configuration to improve the shot- noise limited sensitivity. However, there was no demonstration of recycling on Fabry-Perot prototype interferometer with suspended masses and it was not clear that the recycling is really applicable to full scale detector. 
  This work focused on the most exciting issue of power recycling, recycling gain. The recycling gain is defined as a power enhancement factor of light incident on the interferometer. Main purpose of this work is to apply the recycling technique to 20m interferometer which simulates a full scale antenna in its quality and to demonstrate the high power recycling gain of the order of 10, which is required for TAMA300 and also for other projects. In addition to high recycling gain, study of lock acquisition sequence of high recycling gain interferometer was also an important subject of this thesis. 
  In order to realize a high recycling gain, loss control of optics and interferometer is pretty important since a recycling gain is roughly proportional to the inverse of the total loss of the interferometer. Resulting recycling gain of 450 was reported for simple Michelson interferometer with suspended mirrors. On the other hand, FP Michelson interferometer with fixed mirror table top experiments demonstrated the recycling gain of 18 at the time when this experiment started. The discrepancy between two cases is mainly comes from the difference in reflectivity between simple mirrors and combined FP cavities. Further more, in case of FPMI with suspended mirrors, misalignments of mirrors degrade the contrast of Michelson interferometer as well as reflectivity of FP cavity. Therefore, it is not obvious to attain the high recycling gain with FPMI prototypes. 
  Among several possible candidates of serious interferometer loss, poor reflectivity of arm cavities due to mirror loss and contrast defects of the Michelson interferometer caused by misalignment of mirrors were predominant in the case of 20m interferometer. For the loss of optics, the quality of mirror coatings were extremely improved to have total loss of below 30ppm/optics. This was the first measurement of total loss for 10mm-size beam and best value for mirrors which are used in prototype interferometers. Further more, wave-front sensing technique was introduced as an alignment control system of the mirrors to stabilize the optical fluctuations of the interferometer, It was first demonstration of WFS on the suspended mirror interferometer.
  As a result, 20m prototype interferometer locked with sufficiently high power recycling gain of over 12. This is highest gain ever reported in the world as a suspended mirror Fabry-Perot Michelson interferometer. The whole interferometer was acquired lock by both sequential and automatic locking method within a minute typically. Furthermore the remaining gain fluctuation due to mirror misalignment was sufficiently suppressed by engagement of wave-front sensing technique and stable operation was realized. Success of this work on high gain recycling and implementation of automatic alignment control system using wave-front sensing on 20m interferometer marks significant progress towards achieving full-configured interferometer., application/pdf, 総研大甲第389号},
 title = {A Recycled Laser Interferometer for Gravitational Wave Detection},
 year = {}
}