1. Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, 855 North 16th Street, Lincoln, Nebraska 68588, United States
2. Department of Chemistry, University of Nebraska-Lincoln, 639 N 12 Street, 651 Hamilton Hall, Lincoln, Nebraska 68588, United States
3. Department of Mechanical & Materials Engineering, University of Nebraska-Lincoln, 900 North 16th Street, West Nebraska Hall 342, Lincoln, Nebraska 68588, United States
4. Laser Center, University of Latvia, Jelgavas St 3, Riga LV-1004, Latvia