Basic Optics for the Astronomical Sciences

This text was written to provide engineers and students of astronomy an understanding of optical science—the study of the generation, propagation, control, and measurement of optical radiation—as it applies to telescopes and instruments for astronomical research in the areas of astrophysics, astrometry, exoplanet characterization, and planetary science. The book provides an overview of the elements of optical design and physical optics within the framework of the needs of the astronomical community

Speckle interferometry

We have presented the basic mathematical treatment of interferometry in the optical domain. Its applications in astronomical observations using both the single aperture, as well as the diluted apertures are described in detail. We have also described about the shortcomings of this technique in the presence of Earth's atmosphere. A short descriptions of the atmospheric turbulence and its effect on the flat wavefront from a stellar source is given. The formation of speckle which acts as carrier of information is defined. Laboratory experiments with phase modulation screens, as well as the resultant intensity distributions due to point source are demonstrated. The experimental method to freeze the speckles, as well as data processing techniques for both Fourier modulus and Fourier phase are described. We have also discussed the technique of the aperture synthesis using non-redundant aperture masks at the pupil plane of the telescope, emphasizing set on the comparison with speckle interferometry. The various methods of image restoration and their comparisons are also discussed. Finally, we have touched upon certain astrophysical problems which can be tackled with the newly developed speckle interferometer using the 2.34 meter Vainu Bappu Telescope (VBT), situated at the Vainu Bappu Observatory (VBO), Kavalur, India.Comment: 32 pages tex files including figure

Integrating OCT into Surgical Systems and Monitoring Vibrations

Imaging of the hearing structures can yield information regarding their function as well as insight into the abnormalities and adverse conditions that affect them. Improvements in the acquisition techniques and the quality of imaging systems can contribute to the understanding and treatment of these conditions. Optical coherence tomography (OCT) imaging technology has evolved to the point where systems can deliver 2D cross-sectional images, 3D structural volumes, and functional information regarding the motion of the sample. The information is valuable, but while research systems continue to evolve and become more advanced there is a disconnect between the researcher and the clinician. Translation of research based imaging systems into the clinical field is an important step in future development and adaptation. This thesis is focused on the development of a packaged optical coherence tomography system and the design of a phase-stable surgical microscope OCT system that can easily be introduced into the clinical field

Integrating OCT into Surgical Systems and Monitoring Vibrations

Imaging of the hearing structures can yield information regarding their function as well as insight into the abnormalities and adverse conditions that affect them. Improvements in the acquisition techniques and the quality of imaging systems can contribute to the understanding and treatment of these conditions. Optical coherence tomography (OCT) imaging technology has evolved to the point where systems can deliver 2D cross-sectional images, 3D structural volumes, and functional information regarding the motion of the sample. The information is valuable, but while research systems continue to evolve and become more advanced there is a disconnect between the researcher and the clinician. Translation of research based imaging systems into the clinical field is an important step in future development and adaptation. This thesis is focused on the development of a packaged optical coherence tomography system and the design of a phase-stable surgical microscope OCT system that can easily be introduced into the clinical field

Manufacturing Metrology

Metrology is the science of measurement, which can be divided into three overlapping activities: (1) the definition of units of measurement, (2) the realization of units of measurement, and (3) the traceability of measurement units. Manufacturing metrology originally implicates the measurement of components and inputs for a manufacturing process to assure they are within specification requirements. It can also be extended to indicate the performance measurement of manufacturing equipment. This Special Issue covers papers revealing novel measurement methodologies and instrumentations for manufacturing metrology from the conventional industry to the frontier of the advanced hi-tech industry. Twenty-five papers are included in this Special Issue. These published papers can be categorized into four main groups, as follows: Length measurement: covering new designs, from micro/nanogap measurement with laser triangulation sensors and laser interferometers to very-long-distance, newly developed mode-locked femtosecond lasers. Surface profile and form measurements: covering technologies with new confocal sensors and imagine sensors: in situ and on-machine measurements. Angle measurements: these include a new 2D precision level design, a review of angle measurement with mode-locked femtosecond lasers, and multi-axis machine tool squareness measurement. Other laboratory systems: these include a water cooling temperature control system and a computer-aided inspection framework for CMM performance evaluation

Mode-Multiplexed Transmission over Conventional Graded-Index Multimode Fibers

We present experimental results for combined mode-multiplexed and wavelength multiplexed transmission over conventional graded-index multimode fibers. We use mode-selective photonic lanterns as mode couplers to precisely excite a subset of the modes of the multimode fiber and additionally to compensate for the differential group delay between the excited modes. Spatial mode filters are added to suppress undesired higher order modes. We transmit 30-Gbaud QPSK signals over 60 WDM channels, 3 spatial modes, and 2 polarizations, reaching a distance of 310 km based on a 44.3 km long span. We also report about transmission experiments over 6 spatial modes for a 17-km single-span experiment. The results indicate that multimode fibers support scalable mode-division multiplexing approaches, where modes can be added over time if desired. Also the results indicate that mode-multiplexed transmission distance over 300 km are possible in conventional multimode fibers

Transient microscopic testing method based on deflectometry

The deflectometry provides an optical testing method with ultra-high dynamic range. In this paper, a microscopic testing method based on deflectometric technique is proposed to quantitatively evaluate the microstructures according to the wavefront aberration. To achieve the real-time and accurate wavefront testing for microstructure evaluation, a color-coded phase-shifting fringe pattern is applied to illuminate the test object. It avoids the sequential projection of multistep phase-shifting fringes in traditional deflectometry, enabling the transient wavefront testing. The feasibility of the proposed transient microscopic testing method is demonstrated by the experiment. The proposed method enables accurate and transient testing of microstructures with high dynamic range, minimizing the environmental disturbance.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]