SuperK Varia, manufactured by NKT Photonics A/S, is a computer-controlled variable-bandwidth filter that turns a supercontinuum white-light source into a powerful single-line laser. Designed for use with the company's SuperK supercontinuum white-light sources, it is a cost-effective and flexible alternative to a monochromator. The system offers a tunable center wavelength in the 400- to 850-nm range and a variable bandwidth between 4 and 100 nm. In contrast to acousto-optic tunable filter technology, it suffers no polarization loss and delivers high-power throughput. Powers of >50 mW per wavelength across the full visible spectrum are achieved with the SuperK Varia and the SuperK Extreme EXW-12, using only a 10-nm bandwidth. The system is controlled through the SuperKontrol graphical user interface.