Miniature lamellar grating interferometer based on silicon technology

Abstract

We present a lamellar grating interferometer realized with microelectromechanical system technology. It is used as a time-scanning Fourier-transform spectrometer. The motion is carried out by an electrostatic comb drive actuator fabricated by silicon micromachining, particularly by silicon-on-insulator technology. For the first time to our knowledge, we measure the spectrum of an extended white-light source with a resolution of 1.6 nm at a wavelength of 400 nm and of 5.5 nm at 800 nm. The wavelength accuracy is better than 0.5 nm, and the inspected wavelength range extends from 380 to 1100 nm. The optical path difference maximum is 145 mm. The dimensions of the device are 5 mm 3 5 mm.Spectrometry is widely used in industry and research laboratories. There are many different methods that are used in a variety of fields. In particular, Fourier-transform spectroscopy is a powerful technique for investigating weak sources with high resolution. At present, an extended range of Fourier spectrometers is commercially available. However, high resolution involves an elevated degree of mechanism precision and therefore large size and high cost. Recently, lower-resolution miniature spectrometers have become attractive because of new applications, expanding opportunities in a remarkable variety of disciplines and industries.

Optical MEMS for Lightwave Communication

“…One such MEMS architecture is shown in Fig. 23, which depicts a reflection phase grating with a variable grating amplitude [114]. The reflected optical power from the grating has a harmonic dependence on the grating amplitude, just like the dependence of traditional Fourier transform spectrometers on the optical pathlength difference.…”

Modular integration of microactuators and micro-optical benches

“…Under consideration of these specifications a choice of suitable microactuators can be done. A lot of microactuators found in literature are using the electrostatic principle working like a condenser [5,6,7] . The force of these electrostatic microactuators is given by:…”

Microspectrometer: From ideas to product

“…The detailed theoretical concept of the micro-fabricated lamellar grating interferometer is described in Ref. [6]. Experimentally, the variable depth of the grating is obtained by realizing a series of fixed and mobile mirrors as shown in Fig 2. The intensity of the zero order of the diffraction pattern is recorded in function of the depth of the grating and then Fourier transformed in order to recover the spectrum.…”