The most important aspect of infrared light sources for near-infrared spectroscopy is to cover as broad a wavelength range of emitted light as possible. The larger this range, the more objects that can be analyzed. In order to determine ingredients or water content, the target object is illuminated with infrared light of a wide wavelength range (usually 650 to 1050 nanometer). Parts of this light are reflected, others are absorbed. This ratio varies from object to object, resulting in a unique molecular fingerprint for each item. The reflected light is collected by a special detector. Then, software processes this data, compares it with documented information stored in the cloud and finally, produces the measurement results.
With its extremely compact dimensions of just 1.6mm x 1.6mm x 0.9mm, the Oslon P1616 SFH 4737 from Osram is the world’s smallest near-infrared LED (NIRED) for spectroscopy applications available in the market – and is only half the size of the previous smallest product in the Osram portfolio. It is not only its compact design that makes this NIRED ideal for use in smartphones, but also its outstanding output of 74mW at 350mA – which is about three times the peak values of earlier products. The new product is also impressive in terms of the radiant intensity in the forward direction at 18mW/sr – which doubles the values of former Osram NIREDs.
The superb performance of the whole wavelength range offers another unique advantage in spectroscopy. The sensitivity of the often silicon-based detectors decreases with increasing wavelength (especially above 950 nanometer). In order to compensate, higher currents were required in the past. Thanks to a new phosphor, the component emits more light at higher wavelengths – with positive effects on the overall energy consumption of the system.