Miniature spectrometers for biochemical analysis

Miniature spectrometers have been demonstrated by mounting micromachined diffraction gratings onto CCD imaging devices. Two implementations are tested: one for high-dispersion and -sensitivity applications, and the other for low-cost consumer applications. The first system shows a dispersion of 1.7 nm/pixel and a resolution of 74.4 for the bandwidth of interest. The free spectral range of the device is designed to be in the visible range for this particular application. The diffraction efficiency of the system is 63%. The second, low-cost system demonstrates a dispersion and resolution of 2.55 nm/pixel and 69.8, respectively. These specifications are comparable to that of a conventional, low-end commercial spectrometer. Results are shown for their applications in biochemical analysis. Further optimization is sought by adding micromachined lenses and creating specialized, computer-generated gratings to compress and shape the spectral signal.