1 Department of Mechanical & Materials Engineering, University of Nebraska-Lincoln 900 N 16th St., W342 NH Lincoln Nebraska 68588 USA alaraoui2@unl.edu.
2 Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln 855 N 16th St Lincoln Nebraska 68588 USA binek@unl.edu.
3 Laser Center, University of Latvia Jelgavas St 3 Riga LV-1004 Latvia.