Abstract: A method for preserving a mechanical alignment of a semiconductor laser (100) by use of a temperature control system (101). The semiconductor laser includes an optical mount (110) for mounting a semiconductor laser diode (131) and optical components (132,133). A thermal device (140) and a temperature sensor (180) are used for heating or cooling the optical mount and the semiconductor laser. The method includes adjusting the temperature of the semiconductor laser at a rate less than a predetermined temperature rate by use of the thermal device so as to minimise temperature-related faults, wherein the predetermined temperature rate is experimentally determined and is adapted to the semiconductor laser.

Abstract: The present invention relates to a method and an apparatus capable of severing or damaging unwanted plants without using herbicides. The present invention relates in particular to an apparatus and a method for differentiating between different types of plants to allow identification of, and thus selective elimination or treatment of, individual plants. According to the present invention, the positioning of and the output power of at least one light generating means is controlled on the basis of information from an image recognition system which is capable of differentiating beween different plants.