The past few years have seen an explosion in consumer adoption of connected and wearable devices, which has been good for photonics. In 2017, nearly 40 million consumers in the U.S. alone (roughly 30 percent of households) are expected to own personal fitness trackers like the Fitbit, several models of which have a little green LED sensor that monitors the heart rate. Smartwatches, like the Apple Watch, with its big display and wristful of sensors and microelectromechanical systems (MEMS) technology, had an installed base of 13 million U.S. users in 2016, which is expected to grow by 21 percent by 2020. The wearables market is set to triple in size to more than $25 billion by 2020. Consumers can scan foods for sweetness or macro-nutrient information using the SCiO, a compact, near-infrared (NIR) spectrometer integrated into a smartphone. Courtesy of Consumer Physics. New developments in consumer wearables may even further expand the amount of optics on our person. The availability of low-cost, compact spectrometers and sensors has driven developers to find numerous new usage models beyond the Fitbit and Apple Watch that may completely change our personal connection to fitness, health care and our homes. Advanced optical technology, along with creative programming, are birthing a whole new cadre of next-generation consumer devices that could create a billion dollar market by 2021. The pocket spectrometer Meet the SCiO, a compact, affordable molecular sensor small enough to fit in a smartphone (Figure 1). Consumer Physics (Tel Aviv, Israel, and San Francisco) released the SCiO sensor to developers in 2014, and it appeared integrated into several consumer devices at the 2017 Consumer Electronics Show (CES) in Las Vegas. Chinese smartphone manufacturer Changhong, for example, launched the Changhong H2 smartphone — the first phone to incorporate the spectrometer and allow consumers to scan foods, liquids, medication or body metrics to identify underlying chemical composition. The phone also incorporates a typical 16-megapixel camera, 6-in. long HD display and a fingerprint sensor for security. Figure 1. The beta app of the SCiO miniaturized NIR spectrometer can measure body fat percentage with a simple scan (left). The resulting spectrum is compared to a user-generated cloud-based database for identification (right). Courtesy of Consumer Physics. At the heart of the SCiO sensor is a compact, near-IR (NIR) spectrometer measuring wavelengths from 750 to 1050 nm in 1.5 seconds at a distance of 5 to 15 mm. A combination of optics, complex signal processing and a cloud-based algorithm combine to measure the amount of fat, carbohydrates or protein in your food, even through a thin rind or skin. A liquid-sensing attachment enables the sensor to measure water, alcohol, caffeine and carbohydrate levels in drinks at concentrations above SCiO’s sensitivity threshold of at least 1 percent. Other potential uses include analyzing construction material, detecting counterfeit currency, identifying active pharmaceutical ingredients and skincare. The development of the apps is ongoing. Also at CES, French manufacturer Terraillon introduced a kitchen scale, the Nutrismart, that weighs and visually scans food with the SCiO spectrometer. The same company also introduced an ultra-slim connected bathroom scale, the R-Link, which synchronizes your weight and body composition with a wellness app on your phone. Terraillon also revealed the HOMNI “smart sleep solution,” which uses sensors, light cycles and sounds to analyze the temperature, light, humidity and noise in the room to provide users with tips on achieving a good night’s sleep. At the Chinese equivalent to CES, the Appliance & Electronics World Expo (AWE) show in early 2017, Haier introduced the first intelligent refrigerator with the capability to identify the source of food odors and, with the SCiO tool, measure the nutritional information in vegetables, fruit and meat. Consumer Physics is in talks with other companies that may integrate the SCiO into wearables and other devices. “Imagine a world where we know much more about the input and output of the human body,” says Dror Sharon, president and co-founder of Consumer Physics. “Each and every person can measure how their body reacts to food, chemicals, weather or oxygen saturation. And it will be fun, combining recreation and wellness. I could see these sensors as a big part of our lives in five to 10 years, much like smartphone cameras are today.” Figure 2. The NeoSpectra Micro is a high-performance, chip-scale Fourier transform IR spectrometer that packages light sources, ASICs, MEMS and detector into a miniature 28 × 18 × 6-mm footprint. Courtesy of Si-Ware Systems. Short stack, wide tack Another company working on integrating a low-cost NIR spectral sensor into numerous wearables and consumer devices is Si-Ware Systems (Cairo and La Canada, Calif.). Si-Ware’s NeoSpectra Micro is a small, chip-scale Fourier transform IR (FTIR) spectrometer (Figure 2) that builds on the success of its larger sibling, the NeoSpectra, which is used in handheld and inline spectrometers in agriculture and the petrochemical and health care industries. The Neospectra Micro, incorporating a MEMS interferometer, a tiny indium gallium arsenide (InGaAs) photodetector, light sources, free space optics and ASICs, will offer an unprecedented, wide spectral range operating from 1150 to 2500 nm, covering the entire NIR and beyond. The sensor will offer a selectable resolution from 8 to 16 nm at 1550 nm, in a footprint measuring 18 × 18 × 4 mm (not including the light source). In as few as two seconds, the device will offer consistent, high-performance sensing of gluten in your food, caffeine in your coffee, pollutants in your soil, and glucose and alcohol levels in your blood — noninvasively, through your skin. Si-Ware integrated the NeoSpectra Micro into an iPhone case for its debut at Photonics West in January 2017. Scott Smyser, executive vice president of world-wide marketing and business development at Si-Ware, expects developer kits to become available by the end of Q2, and production of devices incorporating the sensor to occur by the end of 2017 (Figure 3). Figure 3. The NeoSpectra Micro sensor, which is capable of measuring blood glucose noninvasively, is small enough to potentially build into smartphones and smartwatches. Courtesy of Si-Ware Systems. “Development of such a versatile new technology takes time,” said Smyser. “When Apple put the first accelerometer in the iPhone, its purpose was to sense the orientation of the phone and change it from portrait to landscape. Now, it tracks your motion, it can track how far you’ve run, navigate and help with gaming applications in conjuction with the gyro. Once high-performance spectrometers are widely incorporated into phones and other smart devices, developers will find ways to do x, y and z.” Sharon said, “It’s very challenging to accomplish volume manufacturing of an affordable sensor. The more effort we see toward developing connected technology, the happier I am.” Measuring patients at home Not only does spectroscopy on your person offer the ability to track your body’s response to food, chemicals or exercise, a high-end wearable spectroscopic tool can also give doctors information about a patient’s response to treatment that standard clinical imaging modalities can’t. Researchers at Boston University have designed and tested a range of unprecedented wearable optical technologies to monitor patients at critical points during cancer treatment1. One wearable NIR probe uses diffuse optical spectroscopy to track breast cancer tumors and how they respond to treatment during presurgical chemotherapy, in the first days of treatment, and regularly during treatment to monitor their response (Figure 4). Figure 4. A new diffuse optical wearable probe developed at Boston University is designed to track tumor metabolism and changes in the blood during breast cancer treatment. Courtesy of Fei Teng and Vivian Pera/Boston University. Assistant professor of biomedical engineering Darren Roblyer at Boston University said, “During treatment, a lot of biology is going on that has never been tracked continuously: hemoglobin levels, metabolism and the response of a tumor underneath the skin. Now we have a device that can capture these changes and allow your doctor to personalize treatment more effectively than ever before.” Roblyer and his team used a handheld version of the NIR probe in a multi-center clinical study, tracking the concentration of oxyhemoglobin and deoxyhemoglobin over time. They found that a drop in deoxyhemoglobin in the weeks post chemotherapy may indicate that a breast cancer tumor is more likely to respond and shrink. The next-generation device would be a wearable with many more LEDs and photodiodes that can gather more spatial information about what’s happening underneath the skin. The team is working toward bringing the wearable medical device to commercial reality, so that physicians have more immediate feedback they can use to better understand which patients should be given which drugs, how much and when. “We hope optics can play a large part in how we administer a drug to a particular patient,” said Roblyer. “We hope to increase the likelihood that a patient responds and their tumors shrink, or switch to a different drug more quickly when a treatment stops working.” The potential to change medicine is just one way that optics in wearables and in our pockets can connect us to our homes, health and wellness. “We can only guess how people will use the technology and create things we can’t even imagine,” said Sharon. “Reality has a way of being much more surprising.” Reference 1. F. Teng et al. (2017). Wearable near-infrared optical probe for continuous monitoring during breast cancer neoadjuvant chemotherapy infusions. J Biomed Opt, Vol. 22, Issue 1, 014001.