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Portable spectrometers are being used in more ways than ever to analyse food and, this year, consumers will even be able to purchase handheld spectrometers to check food before they buy. Jessica Rowbury looks at how these spectrometers are being used to test food


n the food industry, spectrometers are not just coming out of the laboratory into the processing plant but even into the shops and supermarkets. Miniaturisation and better manufacturing methods have allowed small, robust, and cost-effective instruments to carry out analysis at different stages of food production without having to take samples to a laboratory. One such product, Ocean Optics’ IDRaman Mini, has been named as a finalist for the SPIE Prism Awards 2014, whose winners will be announced at Photonics West in February. Handheld spectrometers are also being developed for the general public. A team of researchers at the Fraunhofer Institute for Photonic Microsystems (IPMS) in Germany has created a prototype near-infrared (NIR) spectrometer smaller than a sugar cube, which in the future could be integrated into a smart phone. This would enable consumers to check the quality of food before they buy it – whether it be the fructose content in fruit or the fat content in meat.

This September a Canadian company, TellSpec, plans to release a handheld device for the public, so that a consumer can simply point at an item of food to analyse its composition. Fraunhofer IPMS’s miniature spectrometer emits

light from 950 to 1,900nm, which is diffracted on a movable optical grating and collected by a single Hamamatsu uncooled InGaAs photodiode detector. The central element of the spectrometer is a micro-electro-mechanical systems (MEMS) chip that contains the grating and both optical slits and measures just 9.5 × 5.3 × 0.5mm. The individual


gratings and optical gaps are manufactured directly on silicon wafers and diced into individual spectrometers. With this method, a single six-inch wafer is large enough to produce several hundred spectrometers and scientists do not have to adjust the components piece by piece as with conventional spectrometers. ‘That’s the idea for mass production for the spectrometers that would be used in mobile applications,’ said Dr Heinrich Grüger, business unit manager of

all the technology scouts from companies that visit our post in the USA. They would like to integrate the spectrometer – as soon as we can provide it for less than €5. This will take a lot of work.’

Companies would

like to integrate the spectrometer – as soon as we can provide it for less than €5

Sensor and Actuator Systems at IPMS. The next stage for IPMS is to find a partner who can integrate the technology into a marketable device such as smart phone. Pricing is the main challenge, according to Grüger: ‘We have spoken to

Grüger believes that new technology is required to manufacture high volumes of optical components and drive the price down. ‘We can already produce the MEMS component at IPMS cheaply and in high volumes, and Hamamatsu can manufacture the InGaAs

detector at even higher volumes,’ explained Grüger. ‘But the optical components are quite tricky – they are currently produced by ultra-precision milling out of a metal substrate. What needs to be invented is some sort of plastic moulding technology

@electrooptics |


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