Potential for using a digital micromirror device as a signal multiplexer in visible spectroscopy

A digital micromirror device (DMD) was tested to demonstrate its potential as a multiplexing device for the simultaneous detection of visible electromagnetic radiation. Using a Visual Basic program, four sections of the DMD were illuminated by a light source and each region of mirrors was modulated at different low frequencies (14.92, 20.00, 25.00, and 34.48 Hz). A time-domain, multiplexed signal was collected from the sectors and a Fourier transform was performed on these data. The resulting frequency-domain spectrum showed that signal intensities correlated well with what was expected. Three different times were used to establish the best frequency resolution. Using this calculated frequency resolution, a 16 s scan could allow simultaneous detection of up to 240 emission/absorption wavelengths. Data collected also shows the selectivity of micromirror regions and the ability to choose specific regions of the micromirror plane, which could be valuable for a number of spectroscopic techniques.