CCD vs CMOS: Which Spectrometer Should You Choose?

Interview conducted by Alina Shrourou, B.Sc. (Editor)Apr 11 2019

An interview with Ger Loop, describing how CMOS Spectrometer technology offered by Avantes provides higher resolution, communication speeds and faster connectivity, conducted at Photonics West 2019.

What features are key to look out for when selecting a spectrometer?

With spectrometers there are a couple of key things which are important to know in order to select the right model. One of these is sensitivity – ie, how well the spectrometer can detect light photons.

Another is resolution. For applications like Raman and LIBS where sharp peaks need to be detected in the spectrum; the higher the resolution, the better the spectrometer is able to distinguish peaks. This means that it can better identify features like the fingerprint of materials.

For certain applications, timing is very important as the spectrometer needs to be triggered when an event occurs. General requirements like communication and object speed are also important. These are the main key features to understand in order to select the right spectrometer.

How does the EVO series provide faster connectivity and communication? Why is this important?

The EVO series are based on the AS-7010 electronics platform. This platform uses the latest electronics, following USB or USB2, and we have already adapted to USB3.0 . This means higher communication speeds, which is useful for applications where in-line measurements are needed.

If you are measuring an object passing by at a certain speed, you only have a limited amount of time to do your measurement and send it to the computer. The faster that is, the faster you can analyse the objects going underneath it.

Alongside USB3.0 we also offer ethernet communication, which is unique to our spectrometers. This allows a more robust communication protocol, enabling the spectrometer to be integrated into customers’ networks or into their machines easily.

Another advantage of ethernet is that communication can occur over a longer length, meaning the distance between the spectrometer and the computer can be much greater. Where USB3.0 can cover about three meters, ethernet can cover up to 1000 meters. That is why the EVO series offers both USB3.0 and ethernet.

How does CMOS compare to CCD technology in a spectrometer?

CMOS has developed quite quickly in the last few years. Previously CMOS was underperforming for spectrometry from a technical point of view, but thanks to phones and the cameras on phones, the fabrication process of CMOS has recently evolved. The normal CCDs used in standard spectrometers have a more expensive fabrication process which will lead to an underdog position on the long run. AS CMOS technology performs just as well as CCD spectrometers, CMOS has grown to be a suitable alternative to the CCDs.

Please introduce the CMOS 4k offered by Avantes.

We started out with a CMOS with the standard 2K version with 2,000 pixels. With the evolving market of LIBS and Raman, we needed a higher resolution detection of sharp peaks. There is a need to get more pixels in the same range, so that you get more data points. Therefore, we have embraced the 4K which has 4,096 pixels in the array. For high resolution applications we now have suitable 4K spectrometers.

CMOS vs CCD

Are there new products that you are demonstrating at Photonics West?

Yes, at Photonics West we gave some sneak previews of items soon to be released. At the moment there is a lot happening behind the scenes concerning spectrometer developments.

At Photonics West we showed a new light source with a higher power LED than we had before. There are also some neat shutter  accessories directly attached to the spectrometers which can remotely control if light should get into the spectrometer or not.

We also showing a very small spectrometer which offers only the optical part of a spectrometer. The AvaBenchMini. These are particularly for OEM customers who want to use their own electronics.

OEM Spectrometers: AvaBench Optical Benches

How are Avantes acknowledging their 25 year anniversary and what do you hope to aim for going forwards?

Avantes started 25 years ago with two men in a shed. Now, we are an international operating company with offices in the United States and China, distributing to a network all over the world – that is certainly something we are proud of having achieved.

We have now reached a size that enables us to accommodate customers who need large volumes. Our target customers are mostly Original Equipment Manufacturers - who will integrate our spectrometers into their devices.

At a certain point, the volume ramps up and reproducibility becomes very important as each unit has to be the same as the other one. This is essential for this kind of customer. Our production capacity is highly automated at the moment, so that we can meet these requirements. We are growing from a small company serving small customers in the scientific industry, to a bigger company serving the bigger OEM customers. We still need to invest more resources to perfectionise this. Our company will certainly continue to grow for the next 25 years.

About Ger Loop

Ger Loop studied Electronics and was over 25 years active in R&D and Technical Sales. Since 5 years he is Product Manager at Avantes.

As a Product Manager, the primary focus is determine that we develop the right  new products. His primary challenge is to look at what we need to develop in order to give the market a complete product  package. This is done by carrying out market analysis, visit exhibitions and research what it is that customers want.

He  also provides training courses and lectures at universities, as well as within the company. It is his belief that sharing knowledge  is  a winning  formula for the business. By sharing your knowledge, you show people that you are an open, smart and  competent partner.