1. Current Status of Collaboration Research Kyuman Cho and Shinji Miyoki Sogang University, Institute for Cosmic Ray Research and LCGT Collaboration 3 rd Japan-Korea Workshop on LCGT, Dec.21-22 2012 Sogang University. Seoul, Korea KAGRA Collaborators Korea Univ., KIAS, Inje Univ., Korea Univ., Yongji Univ., Seoul National Univ., Korea Atomic Energy Research Institute, Hanyang Univ., Pusan National Univ., KISTI, Korea NIMS, Kyungpook National Univ., Kunsan National Univ., KIAS, IISER-TVM, Phys.S. Univ. of Western Australia, Louisiana State Univ., CCRG Rochester Institute of Technology, Beijing Normal Univ., Inter-University Center for Astronomy and Astrophysics, Moscow Univ., LATMOS/CNRS, Univ. of Science and Technology of China, Inst. for High Energy Physics of Chinese Academy of Sciences, Peking Univ., CMS ITR Taiwan, Maryland Univ., Columbia Univ., Glasgow Univ., Sannio Univ., Shanghai Normal Univ., National Tsing Hua Univ., KAGRA Collaborators ICRR, Univ. of Tokyo National Astronomical Observatory of Japan, High Energy Accelerator Research Organization, Phys.S. Univ. of Tokyo, GSFS Univ. of Tokyo, F.Eng. Univ of Tokyo, Tokyo Institute of Technology, Osaka City Univ., Phys.S. Kyoto Univ., Electro Communication Univ., ERI. Univ of Tokyo, Astro. Univ. of Tokyo, Hosei Univ., AIST, NICT, Phys.S. Osaka Univ., YITP Kyoto Univ., Phys.S. Ochanomizu Univ., ARISH Nihon Univ., S.Niigata Univ., Yamanashi-Eiwa Univ., CIT Nihon Univ., FST Hirosaki Univ., S. Tohoku Univ., S. Rikkyo Univ., S. Hiroshima Univ., S. Ryukyu Univ., FSE Waseda Univ., Gunma Astronomical Observatory, Sokendai, Teikyo Univ., Max Plank Inst. AEI, California Institute of Technology,

2. First Collaboration Activity Period : from Aug 20(mon) to 24(fri), 2012. Miyoki visited Pro.Kyuman Cho in Sogang University to find collaboration items for KAGRA from the point of view of interferometric technique. Thank you very much for the great Pro.Kyuman Cho’s accommodation during my visit (lodge preparation, lunch and dinner discussion, Labo- tour, Office room, communication chances with graduate students …) 3rd Korea-Japan Workshop on KAGRA, Dec.20-21 2012, Korea Sogang Univ., Korea

3. Weekly Activities 3rd Korea-Japan Workshop on KAGRA, Dec.20-21 2012, Korea Sogang Univ., Korea 20 (mon) 21 (tue) Lectures on 1)General Introduction of Challenge to Direct Detection of Gravitational Waves 2)Interferometric Technology for GW Detection 1. -Power Recycled Fabry-Perot Michelson Interferometer using Resonant Sideband Extraction Technique -practical noise sources and their suppression techniques. 3)Interferometric Technology for GW Detection 2. -Interferometer Control as GWDs 4)Introduction of KAGRA GW Observatory and New Fields Driven by the GW detection technique. Lunch discussion and Q and A about lecture. Pro. Kyuman Cho’s introduced me his laboratory. 1)I/Q demodulation for precise and wide range length measurement. 2)Heterodyne interferometer using double pass in AOM. 3)Free space optical LAN network 4)Birefringence in vacuum. Lunch Discussion. Q&A about the last lecture.

4. Weekly Activities 3rd Korea-Japan Workshop on KAGRA, Dec.20-21 2012, Korea Sogang Univ., Korea 22 (wed) 23 (thr) 24 (fri) Collaboration Item Search. Seoul Tour by Graduate Students. Social Dinner with Graduate Students. It’s a very good chance for me to hear raw voices of situations of students in Korea, including foreign student acceptance. Collaboration Item Discussions. Dinner Discussion with Professors. Collaboration Item Search.

5. Possible Collaboration Ideas 3rd Korea-Japan Workshop on KAGRA, Dec.20-21 2012, Korea Sogang Univ., Korea Mirror curvature measurement using Heterodyne interferometer using a double pass in an AOM. (MIR ?) Mirror surface reflectivity monitoring system during operation. (AOS?) Mirror local motion sensor with wide range. (AOS?, Detchar? VIS?)

6. Techniques from Prof. Cho 3rd Korea-Japan Workshop on KAGRA, Dec.20-21 2012, Korea Sogang Univ., Korea Heterodyne interferometer using double pass in AOM Can be used for measuring the radius of curvature of the mirror or controlling the tilt of the mirror AOM PBS QWP PD1 PD2 M3 Incident Beam AOM Driver i1i1 i2i2 DA +-+- To RF input of the I/Q-demodulator To LO input of the I/Q-demodulator i1-i2i1-i2 Mirror

7. Techniques from Prof. Cho 3rd Korea-Japan Workshop on KAGRA, Dec.20-21 2012, Korea Sogang Univ., Korea Balanced interferometer for measuring radius of curvature of a mirror or controlling the tilt of a mirror PD 1 QWP PBS 2 PBS 1 PBS 3 HWP 2 RP P 2 HWP 1 P 1 PD 2 Mirror

8. Techniques from Prof. Cho 3rd Korea-Japan Workshop on KAGRA, Dec.20-21 2012, Korea Sogang Univ., Korea Wide dynamic range displacement sensor for mirror position control

9. MIF works 3rd Korea-Japan Workshop on KAGRA, Dec.20-21 2012, Korea Sogang Univ., Korea MIF is responsible for the most important and central part of IFO length and alignment control system. It contains most advanced techniques are concentrated for ultra- precise length measurement, that are expected to attract researchers who have same interests. Some techniques are related with SQL beating, Macroscopic- Quantum mechanics and so on. We expect some collaboration researchs in this related fields because you can produce “papers” !

10. Summary 3rd Korea-Japan Workshop on KAGRA, Dec.20-21 2012, Korea Sogang Univ., Korea The collaboration with Pro. Kyuman Cho has just started. Some proposals that were related with MIR, AOS, VIS and DetChar were discussed. We would like to discuss these collaboration with KAGRA subgroup chiefs. We would like to find collaboration items about MIF and future technique for precise measurement system.