1. Department of Biomedical Engineering, College of Health Science, Korea University, San 1, Jeongneung-3-dong, Seongbuk-gu, Seoul 136-703, Republic of Korea
2. Department of Physics, Advanced Center for Laser Science and Spectroscopy, Hampton University, Hampton, VA 23668, USA
3. BioMed Team, Electronics and Telecommunications Research Institute, 131 Gajeong-Dong, Daejeon 305-700, Republic of Korea
4. Devices & Materials Lab. LG Electronics, 16 Woomyeon-dong, Secho-gu, Seoul 137-724, Republic of Korea
5. Department of Mechanical Design Engineering, Korea Polytechnic University, 2121 Jungwang-Dong, Kyonggi-Do, Siheung-City 429-793, Republic of Korea