Diffractive optical elements (DOEs) allow laser beams to be split, bundled, or formed into almost any shape and are used in multiple applications. The food industry, for instance, uses them for laser perforation, when it comes to applying micro holes into packaging for fruit or vegetables. These allow the food to “breathe” and thus extend its storage life. The holes have diameters of between 50 μm and 300 μm depending on the type of food and material.
Only lasers can achieve the required consistency of perforation at these sizes. Using multispot DOEs for this application, the required number of identical laser beams can be generated with one single optical element. Almost the entire energy of the original beam is preserved.
Modified Atmosphere Packaging (MAP) is used to prolong the storage time of fresh food. Instead of air, the packaging contains one or several gases – mostly nitrogen or carbon dioxide. While oxygen is considered undesirable for most other groceries, fruit and vegetables need it for respiration. Micro-holes allow for the necessary exchange of gases, but keep the protective atmosphere inside the packaging.
