1. Institute of Physics, Nanotechnology and Telecommunications; Peter the Great St. Petersburg Polytechnic University; Polytechnicheskaya street 29 195251 St. Petersburg Russia
2. Institute of Problems of Mechanical Engineering RAS; Bolshoj avenue 61, 199178 St. Petersburg Russia
3. Department of Physics and Technology of Nanostructures; St. Petersburg Academic University RAS; Khlopina street 8/3, 194021 St. Petersburg Russia
4. Institute of Photonics; University of Eastern Finland; Yliopistokatu 2 80101 Joensuu Finland