Examining the Development of MASER Innovations with Element Six

Interview conducted by Zoe PeterkinJul 23 2019

AZoOptics sat down with Element Six at the LASER World of PHOTONICS 2019 show in Munich, Germany, to discuss their CVD diamond solutions and their award-nominated MASER innovation.

Please tell us a little bit about Element Six and why you are exhibiting at LASER World of PHOTONICS 2019.

Element Six, part of the De Beers Group, is a world leader in the design, development, and production of synthetic diamond and tungsten carbide supermaterials. Our mission is to deliver extreme performance to our customers through these cutting-edge solutions.

We are here today to promote our CVD diamond solutions. These solutions are used in many different areas, but predominantly in laser applications. Diamond has a unique combination of properties that include mechanical strength, chemical inertness, wide optical transparency, low coefficient of expansion and high thermal conductivity. These properties make it a super optical material for use in applications ranging from broadband spectroscopy to high power density optical windows.

Since this is a laser-based show, both our customers and potential customers are here, meaning we’re in the right place to promote both our synthetic diamond and other solutions in our portfolio.

Element Six’s MASER innovation was a finalist for the Innovation Award at LASER World of PHOTONICS - please can you tell us about it?

We were shortlisted as a finalist for the Innovation Award at LASER World of PHOTONICS, in the optical device category, for our quantum single-crystal diamond MASER.

Using our state-of-the-art chemical vapor deposition (CVD) techniques, Element Six was able to produce a single crystal diamond, with an optimized level of nitrogen-vacancy (NV) color centers. The background defects of the diamond are also below the part-per-million level.

With this development, and in collaboration with University College London and Imperial College London, the world's first continuous-wave room temperature solid-state MASER was created. The device is a microwave analog of a laser, standing for 'microwave amplification by stimulated emission of radiation'.

Until recently, the commercial use of MASERs has been restricted because they only operate at cryogenic temperatures, but our MASER innovation works continuously at room temperature due to the quantum properties associated with the NV color center in the diamond. This will allow MASERs to be used in higher power systems in smaller and more portable designs.

Could you explain the demonstration displayed at your exhibitor stand?

The demonstration we have here shows one of the main properties of diamond; its very high thermal conductivity. This is of importance specifically when managing high power laser beams. We can examine this by comparing it to other materials, such as copper, which is commonly known to have good thermal conductivity.

We have been inviting the attendees to try and cut through a piece of ice with both a copper disc and a disc made from our diamond material. It lets users feel how quickly the cold from the ice is transferred to your fingers, and also how quickly you can push the diamond disc, or the copper disk, into the ice to cut it.

The results always impress people. They’re able to see that the copper disc takes longer to cut through the ice than the diamond disc, and the cold transfer to the fingers through the copper disc is felt a lot later. If they use the diamond disc, they instantly feel the cold of the ice and can see it cutting through the ice a lot quicker. In practise, the diamond disc cuts through the ice five times quicker than copper, which is linked to its thermal conductivity >2000 W/mK compared with copper’s 400 W/mK.

It’s an interesting and exciting experience for many people, and it’s a simple yet effective way of giving people a better idea of diamond's heat transfer abilities.

Other than applications in lasers, what other applications do you cover?

Apart from laser applications, the other application we are showing here is a free-standing polycrystalline diamond (PCD) speaker dome. It is a curved membrane about 30 microns thick that can be used in HiFi to generate the high frequency part of the audio spectrum without any sound distortion.  In this case, it is diamond’s high stiffness and low density that make it the standout material.  Diamond domes are being used in this way by Bowers and Wilkins in their 800 series speakers.

Another application area that we are looking into is heat spreaders. In many high-powered electronic circuits, if the temperature of the application goes up too much or too quickly, then you start to see more failures in your electronic circuits. One way to prevent these failures is to cool the system down. When trying to reduce the temperature and drain off the produced heat, diamond is the best heat spreader you can find.

We have developed different growth processes to make diamond heat spreaders with a wide range of thermal conductivity from ~2x that of copper to more than 5x better.  These different grades allow us to work with our partners and customers to develop an optimized thermal management solution for their electrical system – offering benefits of increased reliability while managing higher power densities.

What do you think makes Element Six unique?

Element Six is 73 years old this year and has been making synthetic diamond for 60 of those years.  We first made R&D versions of these thermal and optical grades of diamond in 1989.  Since then, we have developed and extended the range of grades available, enabling applications as diverse as spectroscopy for drug diagnostics, domes for speaker systems, optical windows for high power CO₂ lasers and even detectors used in the identification of the Higgs boson by CERN.

In all examples, it has been by harnessing diamond’s incredible intrinsic properties to solve some critical end-user problem that has driven us to make engineered diamond a manufacturing reality.

It is a way for our customers to differentiate us from the competition. We introduce systems that are smaller or more powerful than the competition, thanks to the unique properties of our synthetic diamond.

About Henk de Wit

Henk de Wit has served as the CVD diamond optics Business Manager at Element Six since joining the company in 2007. His primary focus is within the business centres on the development of new solutions for existing markets and identification of new application areas. Before joining Element Six, he held a variety of roles and assignments during his 22 years at Royal Philips Electronics.

His assignments with Element Six span a range of roles in R&D, with a particular focus on electronic components, ceramics, imaging devices and optical storage. Henk holds a MS in Chemistry and a PhD in Mathematics and Science.