Abstract: A laser arrangement for generating a twice frequency-converted laser radiation is disclosed, comprising the following: an active medium which by radiation of pump light generates a first laser radiation with a first frequency; a first laser resonator inside of which the first laser radiation circulates while resonating; a first non-linear crystal which is arranged inside of the first laser resonator and is provided and established to convert the first laser radiation into a second laser radiation with a second frequency that is higher than the first frequency; a second laser resonator inside of which the second laser radiation circulates while resonating; a second non-linear crystal which is arranged inside of the second laser resonator and is provided and established to convert the second laser radiation into a third laser radiation with a third frequency that is higher than the second frequency, wherein the first laser resonator and the second laser resonator are arranged relative to each other such that th

Abstract: A laser arrangement has a first optical element, provided and established to convert a first laser beam having a first frequency into a second laser beam having a second frequency, wherein the second frequency is higher than the first frequency, and has a second optical element, which is transmitting for the first laser beam and reflecting for the second laser beam, and which is provided and established to reflect the second laser beam in a direction of reflection. Both the first optical element and the second optical element are movably mounted in such a way that they can be moved relative to a direction of light propagation of the second laser beam.

Abstract: The invention relates to a device for reducing amplitude noise of a light radiation, comprising a first birefringent crystal, which has a first length along a direction of light propagation as well as a first optical axis; a polarization device; a light sensitive element, arranged in such a way that at least a part of a beam of light radiating through the first crystal and the polarization device when the device is in operation strikes the light sensitive element; and a control appliance which stands in operative connection with the first crystal and which is provided and arranged for using a signal generated by the light sensitive element as input variable and for applying a voltage signal as output signal to the first crystal to compensate for the amplitude noise.