The new Optosplit II for life science research

We have been selling our Optosplit image splitter for some while now, and based on the experience gained thereby we have recently introduced a Mark II version.

An image splitter allows a single image to be separated into multiple ones, on the basis of wavelength and/or polarisation, which are focussed onto independent regions of a single camera. This is of value for Fluorescence Resonance Energy Transfer (FRET), ratiometric emission, and any dual-stain preparations where images need to be acquired with high time resolution.

Enhancements include the mounting of the splitting element and filters in a readily interchangeable cube, and a unique and proprietary mechanism for the optimisation of the internal path separation. In conjunction with appropriate software the CAIRN OPTOSPLIT II can significantly widen the scope of any fluorescence imaging system. It is also clear from user reports that the separation of the images in our new splitter is much easier to adjust than in competing products.

The original design allowed the separation of the images to be varied symmetrically by a single easy adjustment, but this has now been enhanced by a further adjustment that allows the separation of the optical pathways within the unit to be varied symmetrically as well. This is a very useful feature, as the required separation depends on the diameters of the individual beams. These in turn depend on the properties of the preceding optics, which can vary over a wide range, especially (as in microscopy applications) where a number of different magnifications may be involved. By adjusting the internal beam separation to be no more than necessary - just like stopping down a camera lens to optimise its performance - the potential for introducing image aberrations is thereby reduced. Please note that this feature is not to be found in competing products as it uses proprietary technology developed by Cairn.

Unlike the original Optosplit the dichroic mirror (or other beam separator) and optical filters are now mounted in a single block, and both the block and the standard-sized optical components within it can be readily interchanged. This is extremely convenient and means that existing filters and dichroic mirrors can be retrofitted into Optosplit cubes, thus saving money.

High-magnification systems, such as microscopes, can introduce chromatic aberration, which means that images separated on the basis of wavelength may not simultaneously be in focus. To remedy this we have also made provision for focus trim adjustments in the individual optical pathways. Furthermore, different probes may vary significantly in intensity, thus limiting the useful dynamic range of the camera. The Optosplit II allows for this by having convenient slots where neutral density filters can be inserted into either or both pathways. We understand that users will also sometimes want to use the full camera chip with either or neither filter in the light path; the Optosplit has simple and flexible controls to make all of these options straightforward.

Most high-end fluorescence imaging software platforms (details below) provide support to facilitate the acquisition and analysis of split images. However, many researchers do not need expensive software to carry out their experiments so we are currently working on no and low cost solutions for separating combined image stacks into their spectral (or polarised) components. We expect to have these in place within a few weeks.