English: Size Matters or Physics Works. In the photo, Vitaliy Mocharsky is between two different "hearts of solid-state lasers" - active elements: the smaller one (on the right in the photo) is a ruby, the larger one (on the left in the photo) is neodymium. Increasing the size of the active element leads to laser pulse energy increasing. Lasers with such large active elements are used for various material treatment and physical purposes, including laser thermonuclear synthesis. But each material and size of the active element is important and finds its application depending on the specific purposes of the laser. Of course, everyone wants to know the size of neodymium in the photo. And so, its size - 45*630 mm.