1. a Department of Chemistry and Biochemistry and Optoelectronic Computing Systems Center , University of Colorado , Boulder, CO, 80309-0215
2. b Department of Physics and Optoelectronic Computing Systems Center , University of Colorado , Boulder, CO, 80309-0390
3. c Department of Electrical and Computer Engineering and Optoelectronic Computing Systems Center , University of Colorado , Boulder, CO, 80309-0425