A method of controlling beam quality and stability of a laser apparatus, the laser apparatus comprising: a tapered diode laser providing first radiation of at least a first wavelength, the first radiation having a multi-lobe spatial intensity distribution with a dominant lobe and lower-power side lobes; the diode laser comprising at least a ridge waveguide and a tapered section, a first contact for injecting a first current into the ridge waveguide, a second contact for injecting a second current into the tapered section, and means for controlling a temperature of the diode laser; and a frequency conversion unit configured to frequency-convert the first radiation from the diode laser and to output the frequency-converted radiation, the frequency-converted radiation having at least a second wavelength different from the first wavelength, wherein the method comprises: - monitoring the power content of the dominant lobe of the first radiation and monitoring a second parameter indicative of a total power of the first radiation; - iteratively determining a combination of respective values of the first current, the second current and the temperature at which combination of respective values the monitored second parameter is equal to or larger than a first threshold, the monitored power content of the dominant lobe is equal to or larger than a second threshold, and a stability parameter indicative of a fluctuation over time of the monitored power content of the dominant lobe is below a third threshold; - and setting the first current, the second current, and the temperature to the determined combination of respective values; wherein the method comprises: - adjusting the first current so as to at least approximately maximise the monitored power content of the dominant lobe, and adjusting the second current until the second parameter is equal or larger than said first threshold; - if the determined stability parameter exceeds said third threshold, determining whether the second current is below a predetermined threshold current; - if the second current is above said predetermined threshold current, adjusting the temperature to a modified temperature setting; otherwise modifying the first threshold; and - adjusting the first current and the second current until the power content of the dominant lobe is equal to or larger than the second threshold and the second parameter is equal to or larger than said first threshold. a tapered diode laser providing first radiation of at least a first wavelength, the first radiation having a multi-lobe spatial intensity distribution with a dominant lobe and lower-power side lobes; the diode laser comprising at least a ridge waveguide and a tapered section, a first contact for injecting a first current into the ridge waveguide, a second contact for injecting a second current into the tapered section, and means for controlling a temperature of the diode laser; and a frequency conversion unit configured to frequency-convert the first radiation from the diode laser and to output the frequency-converted radiation, the frequency-converted radiation having at least a second wavelength different from the first wavelength, wherein the method comprises: - monitoring the power content of the dominant lobe of the first radiation and monitoring a second parameter indicative of a total power of the first radiation; - iteratively determining a combination of respective values of the first current, the second current and the temperature at which combination of respective values the monitored second parameter is equal to or larger than a first threshold, the monitored power content of the dominant lobe is equal to or larger than a second threshold, and a stability parameter indicative of a fluctuation over time of the monitored power content of the dominant lobe is below a third threshold; - and setting the first current, the second current, and the temperature to the determined combination of respective values; - monitoring the power content of the dominant lobe of the first radiation and monitoring a second parameter indicative of a total power of the first radiation; - iteratively determining a combination of respective values of the first current, the second current and the temperature at which combination of respective values the monitored second parameter is equal to or larger than a first threshold, the monitored power content of the dominant lobe is equal to or larger than a second threshold, and a stability parameter indicative of a fluctuation over time of the monitored power content of the dominant lobe is below a third threshold; - and setting the first current, the second current, and the temperature to the determined combination of respective values; - adjusting the first current so as to at least approximately maximise the monitored power content of the dominant lobe, and adjusting the second current until the second parameter is equal or larger than said first threshold; - if the determined stability parameter exceeds said third threshold, determining whether the second current is below a predetermined threshold current; - if the second current is above said predetermined threshold current, adjusting the temperature to a modified temperature setting; otherwise modifying the first threshold; and - adjusting the first current and the second current until the power content of the dominant lobe is equal to or larger than the second threshold and the second parameter is equal to or larger than said first threshold.