We report a miniaturized spectrometer based on Hadamard transformation. The compact spectrometer utilizes a single-pixel photodetector and thus can operate at any wavelengths at relatively low cost. The spectrometer utilizes a MEMS-driven moving mask to encode the light intensity at its imaging slit, and the encoded light is then collected by a single-pixel detector. The light spectrum is recovered through an inverse Hadamard transform after a complete set of encoding is measured and recorded. The spectrometer is experimentally demonstrated with a spectral resolution better than 3 nm covering the full visible spectrum from 400 nm to 700 nm, and is capable of measuring over 200 spectra per second.
Proc. SPIE. 8977, MOEMS and Miniaturized Systems XIII
KEYWORDS: Optical fibers, Electron beam lithography, Transparency, Waveguides, Electrodes, Photonic crystals, Scanning electron microscopy, Analog electronics, Nanoelectromechanical systems, Radio propagation
In this paper, the analog to electromagnetically induced transparency (EIT) in the double-coupled one-dimensional photonic crystal cavities are proposed and experimentally observed. This EIT-like effect is due to the interference of two resonance modes and the leaky propagation mode. A nanoelectromechanical systems (NEMS) comb drive is used to align the two resonant wavelengths up, which is first used in the studies of the EIT-like effect. The fabrication of the device bases on the standard semiconductor process. Finally, the evolution of the EIT-like transmission spectrum with the applied voltages is shown in the last part of this paper.
In this paper, we demonstrate a configuration of optical force actuator based on coupled one-dimensional photonic crystal cavities (1D PCCs). A NEMS structure, which consists of 3 cascaded folded-beam-springs and an electrostatic comb drive, is integrated into the device to finely tune the gap between cavities so that the relation between the cavities’ resonance shift and their gap changes can be precisely and straightforwardly characterized. Resonance modes of the cavities are utilized to drive the spring structures, which can generate much larger optical forces than waveguide modes due to their high quality factors. The even resonance mode produces an attractive force, while the odd mode produces a repulsive force. In addition, there is the thermo-optic effect accompanying with the optical forces. Here, a decoupling method is also introduced by calibrating the relations of resonance shift versus gap change with the help of the NEMS and resonance shift versus temperature variation in advance. The experimental results show that one cavity is pulled to (pushed away from) the other cavity by 37.1 nm (11.4 nm) for the optomechanical actuator proposed here. This kind of optical actuator has the potential applications of all-optical circuits in future communication and sensing systems.
A micro-sized 2-DOF grating laser scanner which is made to vibrate in-plane by an electrical comb-driven circular
resonator drive is fabricated and tested. The frequency response of the prototype scanner in atmosphere to different
driving voltages and the variations of its natural frequency with scanning amplitude are measured. The results are
compared with those from finite element simulations using a comprehensive dynamic model, including the effects of
geometric nonlinearity of the flexural beams under large deformations. The comparison shows that the predictions made
by the developed nonlinear model are generally valid.