Sutter Instrument introduces two new filter changers specially designed for wavelength selection over a wide spectral range to any given nanometer value. The Lambda VF-5™ and Lambda VF-1™ employ the innovative VersaChrome® thin-film filter technology from Semrock® to provide outstanding bandpass characteristics such as high transmission (close to 100%), steep edges and out of band blocking. Since these filters pass an image, they are equally suitable for emission and excitation paths.

A specific wavelength within the wide spectral range of each filter is obtained by adjusting the angle of incidence from 0 to 60 degrees. This tuning causes little or no change in spectral performance of the filter regardless of the state of polarization of the light passing through the filter. The current VersaChrome® series has 7 filters covering 338 to 800nm. By simply selecting the desired center-wavelength on the controller, the Lambda VF-5 automatically moves and tilts one of its five filters into position. Users can select any combination of filters offered by Semrock® for the Lambda VF-5 (which holds up to 5 filters) or any single filter in the series for the Lambda VF-1.

When using the Lambda VF-5 for emission applications, we suggest installation of the 5 filters with the longer center-wavelengths covering from 430nm to 800nm. For excitation applications, we suggest installing the 5 filters with the shortest wavelengths covering 338 to 620nm. For special applications, any combination of 5 filters could be installed in the Lambda VF-5. The compact Lambda VF-1 accepts any single filter in the series. The single VersaChrome® filter installed in the Lambda VF-1 can be changed as needed.

The controller for these new tunable filter changers is a special version of our Lambda 10-B. Users can select the desired center wavelength in 1nm increments from the keypad, or via the serial or USB ports. In addition, we've installed a command set that is similar to that of the standard Lambda 10-b to allow the user to directly select the filter and angle in microstep increments. This allows control of the Lambda VF-5 and VF-1 with minimal changes to existing software supporting the popular Lambda 10-B controller.

The Lambda VF-1 accepts any single filter in the series, which can be exchanged with other filters as needed. This model offers faster switching times as well as a more compact and affordable system. When used with the Lambda VF-1, the controller is able to also control a seperate filter wheel or SmartShutter®.