An electromagnetically driven lamellar grating based Fourier transform microspectrometer

A lamellar grating based Fourier transform micro-spectrometer is presented in this paper in which an electromagnetic actuator is used to drive the mobile facets of the lamellar grating to move bi-directionally. This configuration allows double-sided interferograms to be recorded, thus avoiding problems associated with zero optical path difference (OPD) identification and at the same time satisfying the requirements for large OPD scans. Based on the experimental results, a large deflection of ±62.5 µm is achieved when the electromagnetic microactuator is driven by a current of ±129 mA. To demonstrate the system performance, the spectrum of the combined light beam of a He–Ne laser and a diode-pumped solid-state (DPSS) laser was measured. The two different wavelength components introduced were distinguished with a full width at half maximum (FWHM) spectral resolution around 3.8 nm at 632.8 nm and 3.44 nm at 532 nm.