Joshua Monroe Cobb

Innovative Manufacturing and Test Technologies for Imaging Hyperspectral Spectrometers

Corning has developed a number of manufacturing and test techniques to meet the challenging requirements of imaging hyperspectral optical systems. These processes have been developed for applications in the short-wave visible through long-wave IR wavelengths. Optical designs for these imaging systems are typically Offner or Dyson configurations, where the critical optical components are powered gratings and slits. Precision alignment, system athermalization, and harsh environmental requirements, for these systems drive system level performance and production viability. This paper will present the results of these techniques including all aluminum gratings and slits, innovative grating profiles, snap together self-aligning mechanical designs, and visible test techniques for IR systems.

An LED multiplexer with improved efficiency

Light emitting diodes (LED) have been increasingly used as light sources for projection display. LEDs have numerous advantages as a light source for these applications especially when used with a digital micro-mirror spatial light modulator such as the device offered by Texas Instruments. LEDs create an expanded color gamut, they can be modulated at very high rates (thus, eliminating the need for a color wheel), and they last longer than other light sources. One disadvantage they have is the luminous output is lower than would be desired for most front projection applications. Smaller pocket projectors have used the LED sources successfully, but the luminous output is limited to between 25 and 100 lumens. One of the areas of light loss in the illumination system is in the multiplexer that combines the three colored LEDs into a coaxial illumination beam. In this paper, this loss is quantified and an alternate multiplexer design is proposed.

Advances in diamond-turned surfaces enable unique cost-effective optical system solutions

Corning has developed a number of manufacturing and test techniques to meet the challenging requirements of imaging hyperspectral optical systems. These processes have been developed for applications in the short-wave visible through long-wave IR wavelengths. Optical designs for these imaging systems are typically Offner or Dyson configurations, where the critical optical components are powered gratings and slits. Precision alignment, system athermalization, and harsh environmental requirements, for these systems drive system level performance and production viability. This paper will present the results of these techniques including all aluminum gratings and slits, innovative grating profiles, snap together self-aligning mechanical designs, and visible test techniques for IR systems.

Multi-emitter laser multiplexer using a two-mirror beam shaper

A system was designed and built to spatially multiplex four broad area laser diodes (BALD) and condense the light into a multi-mode fiber with a core diameter of 105 um and an NA of 0.15. The lasers were efficiently combined with an étendue aspect ratio scaler (EARS) optic. The EARS works under the principle of a two mirror beam shaper. We were able to successfully couple more than 87% of the optical energy into the fiber. The design of the optical system and the results of several built systems are discussed.

A laser speckle reduction system

Speckle degrades the contrast of the fringe patterns in laser interferometers that measure rough objects. In this paper, we describe a speckle reduction system that can be used with high speed cameras to increase the frame rates of the interferometer and creates less vibration in the system.