Hollow-core optical fiber based radiation source

A broadband radiation device, comprising: a pulse shaper configured to impose a temporal profile onto an input pump pulse so as to generate a temporally-modulated pump pulse, the temporally-modulated pump pulse having a different temporal profile than the input pump pulse; and a hollow-core photonic crystal fiber (HC-PCF) having a hollow core for confining in use a working medium under a pressure, the HC-PCF being operable to receive the temporally-modulated pump pulse; wherein the temporally-modulated pump pulse is configured to be spectrally broadened by a soliton self- compression process to form broadband output radiation while propagating through the hollow core of the HC-PCF; and said temporal profile is configured so as to configure a spectrum of the broadband output radiation to have target spectrum characteristics.