Affiliation: | (1) Columbia University, 538 West 120th St., 10027 New York, USA;(2) Dept. of Physics, Univ. of British Columbia, V6T 2A3 Vancouver, Canada;(3) Virginia State Univ., 23803 Petersburg, Virginia, USA;(4) Univ. of Tokyo, 113 Tokyo, Japan;(5) NTT Opto-Electronics Laboratories, 162 Tokai, 319-11 Ibaraki, Japan;(6) Univ. of California at San Diego, 92093 La Jolla, CA, USA;(7) Present address: Riken 2-1 Hirosawa, 351-01 Wako-shi, Saitima, Japan;(8) Present address: Dept. of Physics, Univ. of Texas, 78712 Austin, TX, USA |