What gas do Fibre lasers use
High precision field lenses are used in laser machines that use a fiber laser source to increase energy density and collimate laser beams at one point.
All kinds of materials can be cut with laser machines. It is dependent on which type of laser machine your have that will allow you to cut different materials. Laser machines that use CO2 can't cut through reflective metallic materials such as brass, copper and aluminum. However, they are capable of cutting through nonmetallic materials like plastic and wood.