1. a Dept. Physics , Univ. Colorado , Boulder, CO, 80309-0390, USA
2. b Symetrix Corp. , 5055 Mark Dabling Blvd., Colorado Springs, CO, 80918, USA
3. e Faculty of Applied Science, Royal Melbourne Institute of Technology , Melbourne, 3001, Victoria, Australia
4. c Matsushita Electronics Co. , Osaka, Japan
5. d Dept. Electrical Engineering , Univ. Colorado , Colorado Springs, CO, 80933-7150, USA