| 摘要 |
A broadband laser source comprising: a resonant cavity ( 1 ) containing a medium ( 2 ) which emits optical energy ( 3 ) in a continuum of wavelengths in response to application of pump energy ( 4 ) to the medium ( 2 ); a source of pump energy ( 5 ) for producing said optical energy ( 3 ); a frequency shifter ( 6 ) within the resonant cavity ( 1 ); and a tuneable spectral filter ( 7 ) within the resonant cavity ( 1 ), and the apparatus being such that in use the tuneable spectral filter ( 7 ) has a peak wavelength which is repeatedly swept in a substantially resonant fashion over a wavelength range equal to, or a fraction of, a linewidth of the broadband source such that the rate of change of the peak wavelength of the tuneable spectral filter ( 7 ) is substantially equal to the rate of change of the frequency of the optical energy ( 3 ) as it is frequency shifted within the resonant cavity ( 1 ) by the frequency shifter ( 6 ).
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