We discuss the design of CCD imaging lenses with hybrid diffractive/refractive optics. The hybrid lenses are made of optical grade plastic materials. We have been able to significantly reduce the number of elements while maintaining very high optical quality. This paper describes the conception, design and development of hybrid lenses which combine excellent optical quality with low manufacturing costs. The new lens has high resolution, ultra-low geometric distortion, very light weight and low production cost.
A new and improved railroad crossing roundel lens with 12 inch diameter, 0.21 inch thickness using polycarbonate was designed and manufactured. This design meets or exceeds all the recommendations by the Association of American Railroads. The combination of the new design, precision tooling fabrication, and computer-controlled processing technology has allowed this new design to out-perform the existing products on the market.
The development and testing of lens array prototypes for human use is described. The major issues addressed during this effort were the optical gain achievable from individual lenslets, visual acuity of the overall device, overall device weight and cost. We describe the techniques used to develop lens array devices using off-the-shelf glass achromats which provided large optical gain and high visual acuity. We then describe the development of plastic achromats which provide equivalent visual performance at a fraction of the cost and weight of the glass prototypes.
Volume holograms may be used to make rejection filters which have narrow spectral bandwidths. A unique, and potentially useful, feature of such holographic filters is that the reflecting planes (Bragg planes) need not be parallel to the substrate. For example, spherical holograms (holograms of a spherical mirror) can be made on flat substrates. The slant angle, defined as the angle between the Bragg planes and the substrate, in this case will increase continuously from the center of the hologram to the edge. It has been observed, however, that when such holograms are made in the DuPont photopolymers the playback wavelength is a function of the slant angle. Under identical exposure and processing conditions the playback wavelength increases with increasing slant angle. The degree of shift with slant angle is affected by the presence and type of cover film or cover material used to protect the photopolymer during exposure and processing. In addition to the anomalous spectral shift, the line shape of the reflection band is distorted and the distortion is a function of the playback angle. The results of the experimental observations are reported and discussed.
Application of non-imaging optical concentrators to infrared light detection is discussed. It is shown that dielectric non-imaging concentrators can enhance the sensitivity of IR detection systems with minimal reduction in the field of view. Potential laser warning applications are discussed.
Experimental results on multiline holographic notch filters in Du Pont photopolymer by multiplexing are reported. Two-line filters have achieved peak optical densities greater than 2 at each wavelength. A brief review of the theory is given. Experimental results are compared with theoretical predictions.
It is shown that the nonlinearity in the response function of a holographic medium can lead to formation of gratings at the sum and difference frequencies of the exposing standing wave patterns. This nonlinear feature can be ultilized to create reflection holograms at spectral regions where the conventional techniques are not applicable. Specifically it is suggested that NIR or JR rejection filters which are sensorcentered can be obtained using this approach. 1.
We present an approach for solving nonlinear coupled differential equations using personal computer spreadsheet programs. This approach is used to model the phenomena of bleaching and dynamic filtering in saturable absorbing media. The numerical results are presented. Because of their convenient features 3-D spreadsheet programs are useful for modeling many similar physical phenomena. 1.
An optical system for laser eye protection application is presented. The optical device includes a first lens having a positive power of magnification a second lens having a negative power of magnification and a flat interference based reflector(s) between the two lenses. Incoming light rays are redirected by the lenses so that they pass through the interference filter at normal incidence. 1.