1. Optical Laboratory, Department of Mechanical Engineering, Oakland University, 2200 N. Squirrel Rd., Rochester, Michigan 48309, USA
2. Department of Mechanical Engineering, Lawrence Technological University, 21000 W. 10 Mile Rd., Southfield, Michigan 48075, USA
3. Ngee Ann Polytechnic, 535 Clementi Road, Singapore 599489, Singapore
4. School of Instruments Science and Optoelectronic Engineering, Beijing Information Science and Technology University, Beijing 100192, China