摘要 |
A pumping system 5 for pumping a gain medium for example of a laser. Preferably, the gain medium is an end pumped Nd:YAG. The system comprises a radiation source having a plurality of laser diode emitters 10 (a-e) in a stack, wherein at least one of the emitters is configured to produce radiation having a different wavelength or a different band of wavelengths to at least one other of the emitters at a given temperature. The pumping system may be configured to selectively activate individual emitters according to an output of a temperature and/or optical sensor 30a, 30b which senses a parameter of the pumping system. The pumping system may include a drive unit 15(a-e) controlled by a controller 25 . The controller may be configured to activate, fade or switch to an emitter having an output with a higher wavelength than a currently or previously active emitter if the wavelength of the output of the pumping system decreases and/or selectively activate, fade or switch to an emitter having an output of lower wavelengths than the currently or previously active emitter if the wavelength of the output of the pumping system increases. |