Many astronomical studies require obtaining detailed information about the spectrum of a celestial object, for which various types of spectrometers are effectively used. In the case of extended fields, it becomes necessary to optimally match the field image of an objective and the entrance slit of a spectrometer. For that, an optical scanning system is used. However, it becomes impossible to capture different events in real time this way. For the simultaneous capturing of a wide field, it is efficient to use an integral field unit (IFU). IFU is the optical system that allows slicing and transforming of a field into a set of long slits that are fed to a spectrometer. The design of the IFU optical system for the solar telescope-coronagraph (LST-3) is presented. LST-3 is the telescope with the main mirror of 3m, and it should operate in the wide spectral range, 0.4-1.6 μm. The telescope's objective field of rectangular shape, (1.1 x 2.2) mm, is transformed in two steps: slicing the image and reorganization of sub-images into a set of 8 long slits, (0.018 x 18.6) mm. The reorganization is performed using the system of two flat mirrors. The mirrors are rotated around two axes, which entails the accumulating error of a sub-image position in the image plane. For studying the offset error in an IFU, a simulation was performed. The expression of the error function makes it possible to consider it when using an IFU, while maintaining high spatial resolution and co-directionality of sub-image apertures in the slit plane. As a result of the work, it was confirmed that the use of two flat mirrors for geometric image transformation is possible when designing an IFU.
For solar observations high-resolved spectral instruments are most often used. Many scientific tasks require high spatial resolution along with high spectral one, which, in practice, might be reached through applying the integral field spectroscopy (IFS). In this paper, the ways of the mirror integral field unit (IFU) design for the Solar Telescope- Coronagraph are discussed. The telescope’s main mirror diameter is equal to 3 m, the focal length is 40 m, the spectral range is 0.39 – 1.60 microns. The entrance angular optical field size is 0.75′′ x 12′′, which corresponds to the linear one of 0.145 mm x 2.327 mm at the telescope focal plane. The optical system design of an image slicer is presented. The possibility of the IFU (input NA = 0.0375) development, which cuts the entrance optical field from the telescope into 8 slices, is shown. The size of the final slit is 0.094′′ x 96′′ (0.018 mm x 18.617 mm), which provides 0.1′′ resolution limit.
Generally, classic longslit spectrometers consist of an entrance slit, a collimating lens, a disperser, and a projection lens. High spectral resolution is the main quality function of spectral devices; however, there is also a possibility to achieve high spatial resolution along the slit. Many scientific tasks require high spatial resolution along with high spectral one in astronomical instrumentation. For that, the integral field spectroscopy can be applied. The possibilities of an integral field unit (IFU) optical system synthesis are investigated in this work. The IFU optical system is supposed to be connected to a Solar Telescope-Coronagraph (the main mirror diameter is equal to 3 meters), which operates in a wide spectral range (0,39 - 1,60 microns). Application of integral field units for increasing the spatial resolution of spectral astronomical devices is formulated. The integral field spectroscopy technique description is given as well as the principal concept is shown. Classification of the IFU optical systems (lenslet-, fiber-, mirror-based) is provided. For systems, operating in a wide spectral range, the allreflective design is considered. The system design where the input telescope field (6′′ x 12′′) is divided into 64 slices (0,09′′ x 12′′ each) is proposed. The research results conclude in a computer model of the optical system of the integral field unit with the paraxial optics approach. The proposed solutions may be utilized in the design of optical slicing systems for various applications.
The Student Research Laboratory for Optical Engineering was founded in 2014 at the Dept. of Applied and Computer Optics in ITMO University. Students there work on various optical, design, lighting and technological projects and find like-minded team for creating of coworking-groups in the student laboratory. It is highly difficult to provide practicaloriented activity in the laboratory without the use of elementary optical elements, which are supposed to be components of educational projects and activities. The review of traditional approaches for production of optical elements showed that currently there are no technologies in the optical industry, capable of solving this problem. The produced optical components must meet following requirements: a). to be capable to visualize optical elements work principles; b). to be produced rapid and laborless; c). to be affordable for students. This paper presents results of the experimental work, the technological process and the obtained elements characteristics, which were produced in two different ways. The optical elements angles were measured by goniometer and compared with preset tolerances.
Recently laser technologies are expanded widely among various applications of optical devices. Regarding unique properties laser sources are used in industrial systems, in medicine, in a variety of laboratory equipment, etc. Large number of technical applications requires laser beam reshaping, which presuppose redistribution of optical power in the beam cross-section; particularly to form a flat-top beam with uniform intensity distribution. Traditional inverted lens telescopic systems purposed for the light collimation do not allow to achieve the laser beam reshaping. For this case is possible to use more complicated kind of lens surfaces, such as aspherical ones, or freeforms (both lens and mirror optical systems), microlens arrays and other approaches. Current work describes the optimization model of laser beam reshaping optical system based on aspherical (conic) optics, using Zemax software. Single and two-lens telescopic systems were investigated to reach specified characteristics, results of this studies are shown.
Through the creation of a large number of interactive optical projects in pursuit of this goal, the laboratory has realized that the most effective educational approach is one that presents information in a fun, engaging, and informative manner. Hence, the idea for an optical labyrinth was born. This labyrinth allows students to interact with and learn optical phenomena in real time, presenting tangible benefits for ongoing education of optics and photonics in schools and universities.
Many technical applications need laser beam reshaping, which represents redistribution of optical power in the beam cross-section; particularly to form a flat-top beam. Such systems synthesis requires to develop a specific mathematical model that could be installed then into special commercial software. This work describes laser beam reshaper modeling using two aspherical lens telescopic system. Also are shown approximation equations of refractive aspherical surfaces and the reshaping optical system model applying Zemax software.
In the article it is shown how lightweight a primary mirror of a space telescope can be made by using new material silicon carbide. The article includes theoretical calculations made with the help of software. The main aim of calculations is to get lightweight mirror with small optical surface deflections. The mirror diameter is more than 1 m.
Laser beam reshaper based on two aspherical lens telescope system is presented. Results of computer modeling of a laser beam reshaper and interpolation of refractive aspherical surfaces are shown.
The Student Research Laboratory for Optical Engineering in the ITMO University is the space for self-education and skills improving in the field of optics, optical engineering, photonics, light engineering for all the people: for students, graduates and experts. It is the space for realization of project for the motivated groups of people.
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