Challenge of a Spectrometer on a Chip

We are all familiar with the microprocessor revolution. Electronics evolved from discrete devices to integrated circuits, of higher and higher complexity. With that, performance increased, reliability increased and costs dropped. For analytical instruments, this meant that the room-sized FT-IR spectrometers of the 1970s shrunk to benchtop size in the 1980s, and to laser printer size in the 1990s. Most of this reduction in size was due to the impact of the microprocessor -- the optics have decreased in size only slightly. In many cases, decrease in size of optics has meant decrease in performance, so that the performance of the portable UV-visible devices now available don't match their laboratory cousins.

AXSUN Technologies was founded in 1998 with the vision of miniaturizing and integrating optics in much the same way that had been done with electronics -- producing 'chip-sized' optical engines with the same performance as laboratory instruments, and manufacturing them using automated, semiconductor-style techniques. That vision has been translated into reality. This paper will describe the technology that has been developed and used for the production of these devices, and show, for instance, how a chip-sized spectrometer can produce a 0.1 cm-1 resolution spectrum in much less than one second, with high signal-to-noise.

These devices are not only much smaller than laboratory spectrometers, but are also much more rugged, withstanding large temperature excursions, damp heat and high accelerations. As such, they are very well suited to process analytical applications and do not require a "shelter". They can be mounted outdoors for in-situ analysis and also in vibrating conditions, for instance on a dryer or blender. These process analytical possibilities will also be discussed.