Optical interference notch filters shift to shorter wavelengths with increasing angles of incidence. This phenomenon restricts the filter's field of view and limits the practical application of narrow reflection notch filters. The amount of shift is inversely proportional to the effective average index of the composite film. A method of designing narrow notch optical filters with very broad field of view and controllable bandwidth is demonstrated. Because this method produces a filter that is predominantly composed of the high refractive index material, it will shift on angle less than a typical quarter-wave notch filter. Increasing the effective index of the filter also reduces the separation of S and P-polarized light with angle. This paper presents modeled and measured performance for both mid and far-infrared filters developed using this technique. Narrow notch discrete and rugate filter designs are compared.
This article investigates the use of a multi-conjugate adaptive optics system to improve the field-of-view for the system. The emphasis of this research is to develop techniques to improve the performance of optical systems with applications to horizontal imaging. The design and wave optics simulations of the proposed system are given. Preliminary results from the multi-conjugate adaptive optics system are also presented. The experimental system utilizes a liquid-crystal spatial light modulator and an interferometric wave-front sensor for correction and sensing of the phase aberrations, respectively.
A review of micro-optics technologies with special emphasis on the technology developments at Hughes Danbury Optical Systems, Inc. (HDOS) is presented. This includes both diffractive and non-diffractive techniques. As the user systems become more and more complex, the requirements imposed on micro-optic components become more demanding and, subsequently, one technology cannot presently accommodate all the system specifications. At HDOS, state-of-the-art advancements are being achieved with at least two technologies that appear to be adequate for today’s system applications.
This paper discusses the effects of an etching process on the optical figure of a microlens transferred from photoresist to an underlying substrate. I state a general equation for the evolution of a surface under etching conditions. I then show how isotropic and anisotropic etching conditions behave within this surface evolution theory. I demonstrate how ion milling is not an anisotropic process when eroding 3-D surfaces. Finally, I show that this behavior leads to aberrations in microlenses when subjected to ion milling as a pattern transfer technique.
The laser assisted chemical etching technique (LACE) is capable of generating high quality aspheric microlenses, as well as other miniature components such as prisms and waveguides. Using a calculated intensity map it is possible to individually specify the optical properties of each element in the array. To date, arrays of high quality lenslets have been fabricated with specifications ranging from f/0.7 to f/10 with spacing of 50 to 300 (mu) . Microlenses have been generated in glass, silicon, CdTe and sapphire having 95 fill factors with figure quality better than 1/10th wave.
An essential component in laser diode array systems is the micro-optic system
used for collimation and shaping of the output beams from indMdual elements of the
laser array. Candidate micro-optic technologies include photolithic arrays, gradient-index
optics, binary optics, and laser-assisted techniques. For the present work, a Mach Zender
interferometer was constructed for evaluating wavefront quality. This instrument was
used to select a lensiet array for an external cavity phase locking öxpement involving a
2 x 5 element monolithic surtace-emlthng laser diode array.