[1] Princeton Univ, Joseph Henry Labs Phys, Princeton, NJ 08544 USA
[2] Natl Univ Singapore, Dept Mech Engn, Singapore 117575, Singapore
[3] Princeton Univ, Lewis Sigler Inst Integrat Genom, Princeton, NJ 08544 USA
[4] Princeton Univ, Dept Mech & Aerosp Engn, Princeton, NJ 08544 USA