When specifying optical surfaces of complex shape, polynomial representation methods are often used. However, if the equation of the curve is not described by a standard polynomial, the approximation error at the edges of such functions increases sharply - this introduces huge oscillations. Freeform surfaces of a complex geometric representation are achieved often as a result of design of beam shapers. Spline methods allow minimizing the effect of oscillations after the surface approximation of the beam shapers. In this paper, a comparative analysis of methods for approximation of freeform surfaces is given using the example of Focal-piShaper synthesis and single collimating lens with one freeform surface. The approximation results for the Focal-piShaper prove the high efficiency of the spline approximation, while in the case of aberration-free collimating lens it is preferable to use polynomial regression.
The study of an in-line NIR multichannel spectrophotometer system is performed in terms of energy efficiency and uniformity of dynamic range in the fiber-optic bundle. Recommendations for choosing an optical design between the afocal and focal probing systems are formulated based on comparison of reflection and transmission operation principles as well as determination of working wavelength ranges and analysis of spectral characteristics of the entire system, from source to receiver. In result, for the afocal system, uniformity of 0.09 was achieved with an energy efficiency of 30.4 percent. A spectrophotometer with a combination of the focal forming system and sapphire windows in a flow cell can achieve a power variation coefficient of 0.165 with a power efficiency of 15.3%.
The operation of an optical system in a wide spectral range is an essential characteristic of modern research instruments. This is especially true for systems for studying objects, access to which is difficult or short-term. Work with such objects often takes place in conditions that are far from laboratory ones, including temperature differences, which at certain values make it unacceptable to use cemented optical elements. In turn, cemented doublets are a classic of chromatic aberration correction, which are the larger, the wider the required spectral range. The paper describes approaches to the selection of glass combinations for optical systems operating in the spectral range of 0.3…1.06 μm for temperature ranges of 5 °C…45 °C, -10 °C…50 °C, -50 °C… 80 °C. Linear expansions of materials and chromatic aberrations correction methods are studied. The results were obtained due to design experience of a wide-spectrum lens with a focal length f'=20 mm and F/# of 6.
The paper gives a detailed description of the program VietGOS for automatized synthesis of two-lens and three-lens lenses based on the theory of third-order aberrations. With its help, the synthesis of high-aperture objectives in the visible and infrared spectrum regions and 4-color superachromate was carried out. This program helps an optical engineer to significantly simplify and speed up the synthesis process of two-lens and three-lens objectives with the required characteristics.
In oil and gas production, it is important to determine the type and chemical composition of the formation fluids in the pipeline in real time. Different types of the hydrocarbon formations present in the downhole environment have distinct optical characteristics, such as spectral transmittance, diffusion, fluorescence and refractive index. In the formation sampling and testing, knowing the refractive index of a downhole fluid makes it possible to identify the fluid (water, gas or oil), estimate various properties, such as salinity and crude oil density, and monitor the cleanup processes. The paper describes a new design for an on-axis inline process refractometer for continuous fluid measurements using a defocusing imaging technique. Design principles for the refractometer are discussed, the dependence of the defocus effect on the refractive index is calculated. Experimental energy distributions for different liquid samples are obtained and analysed.
Laparoscopic and endoscopic instruments for minimally invasive surgery are widely used and developed. Previously, author proposed an optical system for an endoscope operating in the long-wavelength IR spectral range [1] for thermal monitoring of biological tissue during surgery. The system is a sequence of germanium lenses. This paper discusses energy performance of the resulting system. The analysis of the long wave infrared range (LWIR) detectors is presented, absorption and throughput is evaluated. Signal-to-noise ratio of the resulting system is calculated.
In the field of biomedical optics, laparoscopes for high temperature treatment of various internal tissues are widely used. With the help of medical endoscopes, it is possible to examine the internal cavities of the human body, biopsy, administer medications, remove tumors, and use laser radiation for surgical and therapeutic purposes. To achieve high performance of optical system’s combination of components made of optical polymers which are transparent in the long-wavelength spectrum are proposed. Technological aspects of optical systems are observed. Computer modeling of infrared endoscope system using Zemax software is presented. Selection of appropriate optical materials is described. Discussion of effective introduction of polymer components into the optical design is provided. Optical performance of the achieved endoscopic systems is shown.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.