<title>Micromechanically controlled diffraction: a new tool for spectroscopy</title>

Abstract

The control of optical wavefronts can be accomplished in many ways and a wide array of static optical components have been developed to address this task. However, for many applications, the use of static optics limits the usefulness of the system. With the recent development of advanced micromachining methods, a new degree of flexibility has been introduced. The application of Micro-Electro-Mechanical Systems (MEMS) technologies to the field of optics has opened new doors for reconfigurable surfaces which can control the reflection, transmission or diffraction of light. This paper will present one such class of devices based on the patented MEMS Compound Grating (MCG) in which a mechanical structure is created that can alter the diffractive behavior of the device through the active reconfigurration of the surface. The rulings of the MCG consist of doubly constrained beams with a custom electrode structure for controlled electrostatic adjustment. Using this ability to actively influence the diffraction of incoming light, increased information can be extracted without the addition of extra optical components. For example, this unique feature can resolve the order- wavelength uncertainty in as spectral instrument thus removing the limitation of free spectral range typical of spectrometers based on conventional diffraction gratings. This ability has implications for a wide variety of optically based sensor systems. The current status of the MCG development will be presented including materials and performance issues and initial integration into both commercial and custom, prototype spectrometers.