The Global Ecosystem Dynamics Investigation (GEDI) instrument was designed, built, and tested in-house at NASA’s Goddard Space Flight Center and launched to the International Space Station (ISS) on December 5, 2018. GEDI is a multibeam waveform LiDAR (light detection and ranging) designed to measure the Earth’s global tree height and canopy density using 8 laser beam ground tracks separated by roughly 600 meters. Given the ground coverage required and the 2 year mission duration, a unique optical design solution was developed. GEDI generates 8 ground sampling tracks from 3 transmitter systems viewed by a single receiver telescope, all while maximizing system optical efficiency and transmitter to receiver boresight alignment margin. The GEDI optical design, key optical components, and system level integration and testing are presented here. GEDI began 2 years of science operations in March 2019 and so far, it is meeting all of its key optical performance requirements and is returning outstanding science.
Ovarian cancer is the most deadly gynecologic cancer, a fact which is attributable to poor early detection and survival once the disease has reached advanced stages. Intraoperative laparoscopic volume holographic imaging has the potential to provide simultaneous visualization of surface and subsurface structures in ovarian tissues for improved assessment of developing ovarian cancer. In this ex vivo ovarian tissue study, we assembled a benchtop volume holographic imaging system (VHIS) to characterize the microarchitecture of 78 normal and 40 abnormal tissue specimens derived from ovarian, fallopian tube, uterine, and peritoneal tissues, collected from 26 patients aged 22 to 73 undergoing bilateral salpingo-oophorectomy, hysterectomy with bilateral salpingo-oophorectomy, or abdominal cytoreductive surgery. All tissues were successfully imaged with the VHIS in both reflectance- and fluorescence-modes revealing morphological features which can be used to distinguish between normal, benign abnormalities, and cancerous tissues. We present the development and successful application of VHIS for imaging human ovarian tissue. Comparison of VHIS images with corresponding histopathology allowed for qualitatively distinguishing microstructural features unique to the studied tissue type and disease state. These results motivate the development of a laparoscopic VHIS for evaluating the surface and subsurface morphological alterations in ovarian cancer pathogenesis.
A volume holographic imaging system maps the spectral-spatial, four-dimensional data set to a two-dimensional image
array, allowing simultaneous imaging of multiple projections of the spatial and spectral content from different depths
within biological tissue samples. The volume holographic imaging system uses dispersion to increase the lateral field of
view. This results in spectral performance characteristics that are unique to volume holographic imaging systems. We
review the principle of operation of the volume holographic imaging system and aberrations due to the dispersive nature
of a volume hologram. We report our experimental results of spectral performance present in a volume holographic
In this paper we review volume holographic imaging techniques for 3D imaging. Our investigation focuses on
holographic imaging systems that operate with broadband illuminator sources. This type of imaging system has the
advantage of reducing or eliminating the need for scanning along lateral or axial direction. However, the utilization
of broadband illuminator source produces significant reduction in depth resolution. Modeling and experiments are
presented to describe the dependence of lateral and depth resolution on the hologram parameters.
This past spring a new for-credit course on illumination engineering was offered at the College of Optical Sciences at
The University of Arizona. This course was project based such that the students could take a concept to conclusion. The
main goal of the course was to learn how to use optical design and analysis software while applying principles of optics
to the design of their optical systems. Projects included source modeling, displays, daylighting, light pollution, faceted
reflectors, and stray light analysis. In conjunction with the course was a weekly lecture that provided information about
various aspects of the field of illumination, including units, étendue, optimization, solid-state lighting, tolerancing, litappearance
modeling, and fabrication of optics. These lectures harped on the important points of conservation of
étendue, source modeling and tolerancing, and that no optic can be made perfectly. Based on student reviews, future
versions of this course will include more hands-on demos of illumination components and assignments.
We present the initial results of an imaging polarimeter operating at 632.8 nm that simultaneously analyzes four
polarization states on a single detector array. In a single snap shot, the polarimeter has the ability to characterize the
polarization of a scene by determining the complete Stokes vector. Images are processed to show Degree of Polarization
(DOP), Degree of Linear Polarization (DOLP), Degree of Circular Polarization (DOCP), ellipticity and the angle of
linear polarization. Our approach utilizes a monolithic analyzer that allows us to avoid issues usually associated with
division of amplitude polarimeters such as jitter and tight tolerance requirements. We discuss our optical design,
calibration procedure, and test data.
Simultaneous detection of the Stokes vector and Stokes images over a broad spectrum can be obtained from an achromatic division of amplitude imaging Stokes polarimeter. This is done through the use of a combination of beamsplitters, prisms and achromatic retarders to split the light into four different paths in collimated space and analyze each beam. Once each beam is focused onto the four quadrants of the camera, the Stokes vector, Stokes images and the degree of polarization across the scene can be obtained through the manipulation of the intensities for each image.
Lockheed Martin is developing an innovative and adaptable optical telescope comprised of an array of nine identical afocal sub-telescopes. Inherent in the array design is the ability to perform high-resolution broadband imaging, Fizeau Fourier transform spectroscopy (FTS) imaging, and single exposure multi-spectral and polarimetric imaging. Additionally, the sensor suite's modular design integrates multiple science packages for active and passive sensing from 0.4 to 14 microns. We describe the opto-mechanical design of our concept, the Multiple Instrument Distributed Aperture Sensor (MIDAS), and a selection of passive and active remote sensing missions it fulfills.