A novel method of beam steering, utilizing a mass-produced Digital Micromirror Device (DMD), enables a reliable single chip Light Detection and Ranging (LIDAR) with a large field of view while having minimum moving components. In the single-chip LIDAR, a short-pulsed laser is fired in a synchronous manner to the micromirrors rotation during the transitional state. Since the pulse duration of the laser pulse is substantially short compared to the transitional time of the mirror rotation, virtually the mirror array is frozen in transition at several discrete points, which forms a programmable and blazed grating. The programmable blazed grating efficiently redirects the pulsed light to a single diffraction order among several while employing time of flight measurement. Previously, with a single 905nm nanosecond laser diode and Si avalanche photo diode, a measurement accuracy and rate of <1 cm and 3.34k points/sec, respectively, was demonstrated over a 1m distance range with 48° full field of view and 10 angular resolution. We have also increased the angular resolution by employing multiple laser diodes and a single DMD chip while maintaining a high measurement rate of 3.34k points/s. In addition, we present a pathway to achieve 0.65° resolution with 60° field of view and 23k points/s measurement rate.
A novel Digital Micromirror Device (DMD) based beam steering enables a single chip Light Detection and Ranging (LIDAR) system for discrete scanning points. We present increasing number of scanning point by using multiple laser diodes for Multi-beam and Single-chip DMD-based LIDAR.
Optical angular momentum (OAM) based communication requires multiple OAM modes. Spiral phase plates for OAM generation are lithographically fabricated. Phase profile of the phase plate is evaluated by surface profiler as well as optically by using Mach Zehnder interferometer.
An adaptive pinhole aperture that fits a GE MaxiCam Single-Photon-Emission Computed Tomography (SPECT) system
has been designed, built, and is undergoing testing. The purpose of an adaptive aperture is to allow the imaging system
to make adjustments to the aperture while imaging data are being acquired. Our adaptive pinhole aperture can alter
several imaging parameters, including field of view, resolution, sensitivity, and magnification. The dynamic nature of
such an aperture allows for imaging of specific regions of interest based on initial measurements of the patient. Ideally,
this mode of data collection will improve the understanding of a patient’s condition, and will facilitate better diagnosis
and treatment. The aperture was constructed using aluminum and a low melting point, high-stopping-power metal alloy
called Cerrobend. The aperture utilizes a rotating disk for the selection of a pinhole configuration; as the aluminum disk
rotates, different pinholes move into view of the camera face and allow the passage of gamma rays through that
particular pinhole. By controlling the angular position of the disk, the optical characteristics of the aperture can be
modified, allowing the system to acquire data from controlled regions of interest. First testing was performed with a
small radioactive source to prove the functionality of the aperture.