Method of providing a laser radiation with a laser arrangement including an optical cavity, the method comprising the steps of - receiving and dispersing at least one first electro-magnetic radiation by a dispersive optical first arrangement so as to provide at least one second electro-magnetic radiation, - receiving and modulating the at least one second radiation by an active optical modulator second arrangement so as to provide at least one third electro-magnetic radiation, and - receiving and dispersing the at least one third electro-magnetic radiation by a dispersive optical third arrangement so as to provide at least one fourth electro-magnetic radiation, - causing a spectral filtering of the at least one fourth electro-magnetic radiation relative to the at least one first electro-magnetic radiation by actions by the dispersive optical first arrangement, the active optical modulator second arrangement, and the dispersive optical third arrangement, wherein the laser radiation is associated with the at least one fourth radiation, and - controlling a wavelength of the laser radiation by the spectral filtering caused by the actions by the dispersive optical first arrangement, the active optical modulator second arrangement, and the dispersive optical third arrangement, and - wherein the dispersive optical first arrangement includes a first dispersive element, - wherein the active optical modulator second arrangement is a first optical phase modulator, - wherein the dispersive optical third arrangement includes a second dispersive element, - the method further comprising the steps: - receiving and modulating the at least one fourth radiation by a second optical phase modulator so as to provide at least one fifth electro-magnetic radiation, the optical cavity comprising the first dispersive element, the first optical phase modulator, the second dispersive element, and the second optical phase modulator, and further comprising a Fabry Perot etalon which spectrally filters the at least one fourth electro-magnetic radiation relative to the at least one first electro-magnetic radiation, - driving the first optical phase modulator by a first electrical signal and driving the second optical phase modulator by a second electrical signal, and - modulating the first and second electrical signals such that the laser arrangement switches wavelengths among the transmission modes of the Fabry Perot etalon, thereby achieving a wavelength-varying output. - receiving and dispersing at least one first electro-magnetic radiation by a dispersive optical first arrangement so as to provide at least one second electro-magnetic radiation, - receiving and modulating the at least one second radiation by an active optical modulator second arrangement so as to provide at least one third electro-magnetic radiation, and - receiving and dispersing the at least one third electro-magnetic radiation by a dispersive optical third arrangement so as to provide at least one fourth electro-magnetic radiation, - causing a spectral filtering of the at least one fourth electro-magnetic radiation relative to the at least one first electro-magnetic radiation by actions by the dispersive optical first arrangement, the active optical modulator second arrangement, and the dispersive optical third arrangement, wherein the laser radiation is associated with the at least one fourth radiation, and - controlling a wavelength of the laser radiation by the spectral filtering caused by the actions by the dispersive optical first arrangement, the active optical modulator second arrangement, and the dispersive optical third arrangement, and - wherein the dispersive optical first arrangement includes a first dispersive element, - wherein the active optical modulator second arrangement is a first optical phase modulator, - wherein the dispersive optical third arrangement includes a second dispersive element, - the method further comprising the steps: - receiving and modulating the at least one fourth radiation by a second optical phase modulator so as to provide at least one fifth electro-magnetic radiation, the optical cavity comprising the first dispersive element, the first optical phase modulator, the second dispersive element, and the second optical phase modulator, and further comprising a Fabry Perot etalon which spectrally filters the at least one fourth electro-magnetic radiation relative to the at least one first electro-magnetic radiation, - driving the first optical phase modulator by a first electrical signal and driving the second optical phase modulator by a second electrical signal, and - modulating the first and second electrical signals such that the laser arrangement switches wavelengths among the transmission modes of the Fabry Perot etalon, thereby achieving a wavelength-varying output. - modulating the first and second electrical signals such that the laser arrangement switches wavelengths among the transmission modes of the Fabry Perot etalon, thereby achieving a wavelength-varying output.