The design and development of today’s optical systems were made possible by a theoretical understanding of optical aberrations. Although the subject is still evolving, serious work spans almost four centuries. In this paper, a historical summary of the development of the understanding of optical aberrations is presented by relating the contributions of numerous individuals. The major events and discoveries are also presented in a time-line format on a century by century basis to allow a rapid overview.
Computer based lens design optimization routines have evolved significantly over the nearly five decades of their existence. In this paper the more widely used techniques are examined including some discussion of their strengths and weaknesses. In addition, some popular alternative methods to the conventional techniques are explored highlighting the technical and economic reasons for their development and use.
A solution to the Monochromatic Quartet problem posed at the 1990 International Lens Design Conference 1 is explained in terms of its origins and influences from several photographic and micro lithographic lens designs. Simple considerations are given for the selection of a starting point for local optimization which improve the chances of finding the global optimum.
While it cannot be claimed that this Quartet solution is a practical one, the problem did not require it to be so. It does, however, illustrate several important features of real lenses, and is shown to lie in performance between photographic and microlithographic lenses. The problem specifically excluded catadioptric designs, but a solution that ignores this rule is shown to give a significantly better minimum, illustrating that even the global optimum is local to the space defined by a given set of constraints.
Relaxation of various restrictions has led to new zoom lens types which include multiple zooming groups and advanced concepts for focusing. New designs can now rival fixed focal length lenses for most applications, and with the use of aspherics can be low cost. Gaussian optics and primary aberrations are used to obtain good starting design types.
Most lens designers and optical engineers are quite familiar with the many issues regarding lens design for visible systems. Design forms such as the achromatic doublet, the Cooke triplet, the double Gauss, the telephoto lens, wide angle lenses and others have been around for many years and are well documented in the literature. While thermal imaging systems are very similar to their visible counterparts in many ways, they are also different in many other ways. This paper will discuss the many aspects of lens design for the infrared which are different from visible system designs.
Diffractive lenses have arrived. Literally hundreds of papers have been published1-25 and technology impact reports have been written about the exciting addition of a new tool for the lens designer.1 Sophisticated computer programs have been developed to aid in the optimization of these diffractive phase profiles for a wide variety of applications. Now, several fabrication methods are being pursued to produce these diffractive elements economically. The best known process is the etching of a multi-level relief grating, known as binary optics.2 This process uses sets of computer generated lithographic masks. Another, more recently developed method is Dry Photopolymer Embossing (DPE).3 This replication process uses master holograms. And now, diamond turning is being applied for the machining of these elements.4,5 Diamond turning is especially well suited for infrared optics. As any process has advantages and limitations, so has diamond turning. These advantages and limitations are discussed and general guidelines are presented to aid the designer and systems engineer in the project predesign stage.
The diffractive optical element (DOE) provides unique and improved chromatic aberration reduction for both visible and IR optical systems. The DOE simplifies the optical design form and improves the image quality of refractive optical systems. This paper formulates and analyzes the theory of chromatic aberration correction and compares DOE performance with that of a conventional optical element (COE). It presents several design examples with spectral bandwidth ranging from visible to long wavelength infrared to illustrate the advantages of optical systems using a DOE. DOE improves optical system performance while lowering the cost and weight by reducing the number of lens elements and desensitizing misalignment tolerances.
Head up displays have become essential for the operation of fighter aircraft. A history of their development is described along with a comparison of different configurations from present production and experimental displays. Photometric considerations are discussed. Holographic structure and construction techniques are illustrated.
Recent advances in X-ray sources and optical fabrication techniques have resulted in a resurgence of activity in the field of X-ray and extreme ultraviolet (EUV) imaging systems. Novel approaches to the fabrication of grazing incidence X-ray mirrors and the rapidly emerging technology of enhanced reflectance X-ray multilayers are producing new advances in the areas of X-ray/EUV astronomy, soft X-ray microscopy. X-ray microlithography, and synchrotron source applications. However, traditional optical design and analysis techniques (geometrical ray tracing) are woefully inadequate for predicting the performance oi high resolution imaging systems at these very short wavelengths. The diffraction effects of highly obscured annular apertures (grazing incidence optics) and small angle scattering effects due to residual optical fabrication errors will frequently dominate geometrical design errors in the degradation of image quality. These and other potential pitfalls in the design and analysis of high-resolution X-ray/EUV imaging systems will be emphasized and illustrated by examples in current applications of major interest.
The development of a special purpose telescope is described, which is capable of complete stray light rejection, parfocalization of all wavelengths, and diffraction-limited image quality, all with only "gentle" aspherics, even for a 2.5-meter aperture. The main purpose of this new design is as a solar coronagraph, although there are several other possible astronomical and military applications.
Optical design codes whose optimization routines rely heavily on aberration coefficients proved ineffective in finding "global" optima in the non-rotationally symmetric world of "compact" eccentric pupil telescopes. Manual "steering" of the optimization process resulted in "rediscovery" of the Schwarzschild Principle.
This paper reviews the developments in the design of color corrected lens systems particularly apochromats and superachromats. The historical development of the theory, method of selecting compatible optical materials and design techniques are summarized. Examples of apochromats and superachromats are described and the performance evaluations of these designs are shown.
For laser pointers and designators, far-field analyses based on geometrical optics or Fraunhofer diffraction are often inadequate and erroneous. To obtain useful results, we must apply Fresnel’s diffraction theory, but at the cost of having to abandon a traditional way of defining “focus,” as well as having to invent a new depth-of-focus formula. One consequence of Fresnel analysis is that we may “ray trace” Gaussian beams. Gaussian-beam ray trace is similar to geometric ray trace, but it leads to radically different results that often confound common sense. This paper begins with examples of systems in which geometric and Fraunhofer analyses fail, demonstrates how Fresnel analysis applies, points out the need for precise definitions of focus and depth of focus, and ends with some simple rules of thumb based on wave front aberrations and the characteristic Fresnel number.
Multimirror reflective optical systems have seen significant development in the past 20 years. Advances in computer-aided design, fabrication, and alignment have produced ever higher performance optical systems in response to ever more demanding requirements. From a purely aesthetic standpoint, three-mirror optical forms hold a unique position in performance/complexity space: three mirrors are available, and three aberrations need to be corrected (spherical, coma, and astigmatism).
The purpose of this Critical Review is to provide an overview of the evolution and the state of the art of microscope objective design forms and the related family of optical disk objective design forms. Although these objectives have a venerable history, there are emerging applications, new design forms, and new manufacturing technologies that have recently generated substantial growth in these fields of application. A common goal of both objective families is diffraction-limited performance, but the optical disk objectives have the advantages of a limited spectral range and refocusing for extra-axial objects.
The difficult interface between optics and the human visual system is discussed, particularly in relation to the design of binocular optics. Many sections are also applicable to the simpler case of monocular optics.