Trends in Modularity

Gary Boas, Contributing Editor, gary.boas@photonics.com

Step by step, piece by piece, modularity is finding a home in optics, and microscopy and spectrometry applications are benefiting from the availability of modular systems.

Furniture. Spacecraft. “Dungeons & Dragons” adventures. In each of these you can find modules, independent units or components that combine to make a more complete, more satisfying whole. With the modular approach, you pick and choose the components you want, putting them together in such a way as to meet your requirements effectively. Modularity ensures that your furniture fits perfectly in your room. You don’t have too much couch. You don’t have too little. You have exactly as much couch as you need.

As it is with furniture and spacecraft, so it is with optics-based technology. Recent years have seen greater attention paid to modularity in microscopes, spectrometers and more. This allows customers to build the instrument that precisely fits their needs without having to pay for functionality that they will never use; modularity also enables them to build out an instrument as their needs change and grow. At the same time, modular systems present their own sets of challenges for developers of the technology.

The Leica DMi8 facilitates flexibility and connectivity with its Infinity Port, which provides access to the instrument’s infinite light path, illustrated here. This enables integration of the modules – the lasers and other light sources, for example – that a user would need for a broad range of applications, including FRAP (fluorescence recovery after photobleaching), photoswitching and ablation. Photo courtesy of Leica Microsystems.

Overall, of course, the move toward modularity in microscopy systems is advantageous to all involved. It really can help a broad range of customers, said Bernard Kleine, product manager with Wetzlar, Germany-based Leica Microsystems. Indeed, there are few customers who don’t benefit from it.

In microscopy, he said, users take advantage of modular systems for one of several reasons: affordability, flexibility or upgradability.

In many cases, for example, users need a system for only one, very particular application. Conventional systems can be somewhat unforgiving for these customers. Because they are designed to serve the gamut of users, they necessarily offer a wide selection of functionalities. Now, however, with access to modular microscopy systems, these customers can pick and choose the components (and therefore the functionalities) that they want. This makes for a better, more personalized system, while also helping to keep costs down.

Next up: flexibility. Oftentimes, of course, institutions will purchase a system for multiple users working with a range of applications. And here they will want a variety of configurations.

In the past, it wasn’t always possible to accommodate this, Kleine said. “We could offer some special components, but it was really, really hard to give the customer the right options of different manual or motorized modules,” he noted. Not least because they would need special manual or electronic interfaces to bring all of the components together.

Configurability in lasers is more common on the software side. Shown here are Spectra-Physics’ InSight DS+ ultrafast laser (left), in which software controls >600 nm of wavelength tuning and dispersion precompensation, and the company’s Quasar high-power UV hybrid fiber laser (right), with software-controlled pulse width, pulse shape and repetition rate. Photo courtesy of Spectra-Physics.

The modular systems offered in more recent years have helped to overcome this problem. Here, users can choose the various components they need to assemble a microscope “like Lego, piece by piece,” Kleine said.

Finally, customers can benefit from the upgradability that microscope modularity allows. A platform might be configured exactly to a user’s requirements today, but those needs could change tomorrow. The user might want to add different cameras, illuminations or stages, for example. This is as true for large universities and centers of excellence as it is for starters with limited budgets that anticipate growing over time. A system should be able to accommodate these evolving needs – to be futureproof.

Making a futureproof microscope system isn’t a trivial task, however. To do this, you have to be able to anticipate the major trends of the next several years: Where is the funding coming from, who will be doing the research, and what will they be seeking to learn?

At the same time, you need to make sure that all of the components fit together, and that they will continue to fit together over time. To this end, Leica Microsystems came up with a special fitting process for its modular systems. This was a challenge in itself, Kleine pointed out. “Each and every module gives you some possibility of error or mismatch. So you have to be very, very precise in designing the interface – not on the scale of millimeters or micrometers, but parts of a micron,” he said.

Using the Leica DMi8, researchers have obtained highly detailed images such as this confocal image of a mouse diaphragm (green: nerve fiber, Alexa 488; red: synapses, Rhodamin; blue: muscle fiber, myosin, Dodt contrast). Photo courtesy of Ulrike Mersdorf, Max Planck Institute for Medical Research, Heidelberg, Germany.

Modularity comes with other difficulties as well. Just ask Ger Loop, product manager with Avantes, an Apeldoorn, Netherlands-based developer of fiber optic spectroscopy instruments. The company’s core product line, its spectrometers, has an optical bench design with a range of different components incorporated into it. Here, users can configure the system based on their particular needs, from a small spectral range with high resolution to a broad range with lower resolution, by choosing different gratings and detectors, for example. A programmable electronics board interfaces between the user and the optical bench independently of the chosen detector.

But the expanded configurability of the systems can also make for greater complexity. Any one component in the system will need to be designed to work with all of the possible configurations, said Loop. This is a design challenge for a single component – say, the diffraction grating – and successfully addressing this challenge will require considerable time and effort. And developers must do this X times over, for however many components are included in the optical bench.

“The modular design has more pitfalls and traps than one can count,” Loop said. Working around these calls for a special kind of knowledge and experience on the part of the developers.

Avantes spectrometers, including the ULSi shown here, feature an optical bench design enabling broad configurability of the instruments, as well as a flexible, programmable electronics board that serves as an interface between the user and the various components in the spectrometers. Photo courtesy of Avantes.

Configurability in the laser market While we’re seeing an ongoing push toward hardware modularity in microscopy and elsewhere, this is less the case with lasers. If anything, we’re witnessing the reverse. “We tend to see things moving toward plug-and-play solutions,” said Herman Chui, marketing director for Santa Clara, Calif.-based Spectra-Physics. “Configurability is definitely important but more from a software perspective.”

This is especially true because the user base is less technically inclined these days than it once was. It is focused more on end users such as those in the biology arena, for example, who simply don’t have hands-on experience with this kind of technology. “A lot of our customers are not at all familiar with the lasers, but they need them for their work,” Chui said.

For this reason, Spectra-Physics is giving users all the controls they need – the ability to change the power, the wavelength, etc. – at the far more user-friendly software level.

“It’s about making it as easy as we can for the users,” he said.

What has modularity done for you lately?

Modularity is making many scientists’ lives easier by letting them build out the instrument that they want and need. In a phone call from Wetzlar, Germany, Bernd Sägmüller, director of confocal imaging at Leica Microsystems, described several cases where a customer might want to expand a basic confocal microscope – for instance, the company’s TCS SP8, the modular platform for confocal microscopy shown here, in combination with its DMi8 inverted microscope.

Here are “three typical examples of how a standard confocal system evolves and grows,” he said:

1. You have a need to see beyond the barrier of refraction, so you decide to go to superresolution.

2. You are looking to add fluorescence lifetime imaging or fluorescence correlation spectroscopy.

3. You are part of a larger work group using more than just three or four fluorophores in its imaging, so you add a white-light laser to achieve the needed flexibility.

In the past, to adapt to changing needs such as these, users would likely have had to wait until they could purchase a whole new microscope. But now, with increased availability of modular systems, they can update their instruments as the needs arise.