A new concept in confocal microscopy

Regular followers of our activities may well recall that we have been developing what we believe to be the first commercial version of a Programmable Array Microscope (or PAM for short) in collaboration with the laboratory of Dr. Tom Jovin at the Max Planck institute in Goettingen.

Working prototypes have been undergoing detailed evaluation at both locations, and we are delighted to report that the results have been fully living up to our expectations, so we hope to make a full commercial announcement later this year. However, we are already preparing to make a small number of sales to beta test sites, and in any event it would be useful for us to hear from anyone who is potentially interested in this product, so that we can keep you informed of our progress and of the future supply situation, as inevitably the initial availability may be limited.

So what is a PAM exactly? Well, imagine a parallel-scanning confocal microscope working on the same general principles as a Nipkow disc system, but in which the place of the apertures in the spinning disc (through which the excitation and emission light pass) is taken by a static array of apertures which can be opened or closed at will. As well as simulating the moving apertures in the disc, in principle any fixed or moving pattern of excitation and/or detection can be generated by the array, which is a high-speed (ferroelectric) megapixel liquid crystal device. Naturally this offers enormous potential for additional applications such as selective excitation or photobleaching, as well as a broader range of conventional confocal operation. A potentially very useful confocal mode is to simulate a disc in which the apertures occupy a relatively large fraction of the total area. Although this increases the optical efficiency, normally it would significantly degrade the confocality, but our implementation incorporates one of the Goettingen innovations (Journal of Microscopy vol 204 p119), which is also to collect the emission light that falls onto the "closed" apertures on the array and focus it onto a second camera. This is very useful for various image deconvolution strategies to increase the degree of confocality, but since the requirement for two cameras may be both inconvenient and expensive, our implementation also allows the two images to be focussed onto different regions of a single camera.

So how much will one of these units cost? We're aiming for a target price of around 50,000 Euros for the basic PAM unit, including software to control the liquid crystal array. To this you will need to add a microscope (the PAM unit attaches to an imaging port, and in principle just about any microscope so equipped can be used), a camera and acquisition software, and a light source (which could be a laser but our LED light source is a potentially attractive alternative). This makes it very competitive with both laser scanning and Nipkow disc confocals, particularly in view of its much greater versatility. It is our intention to ensure that the PAM is freely available for use with any other suitable equipment. We are currently working with Olympus and Nikon microscopes, Andor IQ software and Ixon cameras. We also intend that early instruments can be configured with QED software and Photometrics Cascade II cameras, with further support to follow soon.