NKT Photonics has introduced its SuperK Varia, a computer-controlled variable bandwidth filter. The Varia is a cost effective and flexible alternative to a monochromator, effectively turning the SuperK supercontinuum white light source into a powerful single-line laser with a 450nm tuning range and a variable bandwidth. The centre wavelength of the pass band can be tuned anywhere in the 400-850nm range, and the bandwidth is variable between 2 and 100nm, making the Varia one of the most flexible filter solutions on the market. The Varia can find use in applications such as fluorescence lifetime imaging, and flow cytometry.