Non-rotational symmetric aspheric surface has many significant advantages, but it still can not be widely used because the limiting that there is no method can tests it precisely. At present, the coordinate contour measuring machine is the main testing method for the aspheric surface with non-rotational symmetric, but the measurement accuracy of this method is not high. In this paper, the method of diffraction compensator (computed graphic holograph) has been adopted to test the combined aspheric surface, which can compensate the phase caused by tested lens. The sample surface is the combined aspheric surface with diameter of 33.84mm, and the process from optical software simulation design, the fabrication of the computed graphic holograph (CGH) to experimental platform built is given in detail after testing via the CGH technology. The simulation results show that the root mean square (RMS) of remnant wave-front error is 0.004 λ, and the peak to valley (PV) is 0.0245 λ. The free-from surface has been tested by Zygo interferometer, and the experimental results show that the RMS is 0.49 λ, the PV is 4.69 λ. The accuracy of the result is higher than that of coordinate contour measuring machine. The system error caused by optical elements analysed is 0.1149λ. The accurate result means that the CGH technology for testing the combined aspheric surface is realized.
According to technical requirements,an apochromatic telescopic optical system which is characterized by the focal length
1.5m~2m,with the visible region spectrum band is needed.The successful design consists in using normal glasses based
on PWC method to get a completely secondary-spectrum-removed and cramped construction telescopic optical system in
this paper.Firstly, by the aberration theory and ZEMAX optical design software,a catadioptric achromatic optical system
composed of a reflecting mirror and a couple of air-spaced negative doublets are designed.The initial configuration of
optical system is calculated by PWC method and the proper couple of air-spaced negative doublets are chosen by the
theory of achromatic.By comparing with various optical systems with different couple of air-spaced negative doublets, it
is found that the combination of the heavy crown glass ZK7 and heavy flint glass ZF3 is effective to correct chromatic
aberration and its secondary spectrum value is minimality.It can conclude that fact with the abbe number of ZK7 is twice
than ZF3 make the good result and give guiding to the design of the same type of optical system. Secondary,according to
the theory of secondary spectrum,the secondary spectrum value to be corrected is analyzed and the compensation can be
changed by adjust the magnification power.The comparison is presented and the final telescopic optical system with
cramped construction is achieved, and the goal of apochromatism and other aberration is reached.
A novel moderate-resolution imaging spectrometer spreading from visible wavelength to near infrared wavelength range
with a spectral resolution of 10 nm, which combines curved prisms with the Offner configuration, is introduced.
Compared to conventional imaging spectrometers based on dispersive prism or diffractive grating, this design possesses
characteristics of small size, compact structure, low mass as well as little spectral line curve (smile) and spectral band
curve (keystone or frown). Besides, the usage of compound curved prisms with two or more different materials can
greatly reduce the nonlinearity inevitably brought by prismatic dispersion. The utilization ratio of light radiation is much
higher than imaging spectrometer of the same type based on combination of diffractive grating and concentric optics. In
this paper, the Seidel aberration theory of curved prism and the optical principles of Offner configuration are illuminated
firstly. Then the optical design layout of the spectrometer is presented, and the performance evaluation of this design,
including spot diagram and MTF, is analyzed. To step further, several types of telescope matching this system are
provided. This work provides an innovational perspective upon optical system design of airborne spectral imagers;
therefore, it can offer theoretic guide for imaging spectrometer of the same kind.
According to technical requirements and the structure characteristics of long-focal-length optical system, the paper
analyzes the advantages and shortcomings of reflective system and refractive system in details. By the aberration theory
and ZEMAX optical design software, a long-focal-length space optical system which is characterized by the catadioptric
configuration,with the spectrum band 500~ 800 nm is designed. And evaluations show that the image quality is close to
the diffraction limit. After being manufactured, the optical transfer function (simplified MTF) of long-focal-length lens is
tested, and it shows that the best focal planes of spectrum 500nm~800nm, 550 nm, 650nm are not in the same position
and deviate greatly, which is chromatic aberration. Whereas, after remeasuring the long-focal-length lens, it is found that
the MTF values of the three wavebands can meet the qualification requirements simultaneously if we defocus 57.7μm
from the best focal plane of spectrum 500nm~800nm. Finally, the cause of chromatic aberration phenomenon in the
measurement of catadioptric optical system is deeply discussed at the first time based on the structure characteristics of
optical system, then the improvement is achieved correspondingly and the results show as below: the full-aperture
spherochromatic aberration of improved optical system is reduced from 0.45μm to 0.25μm, and its MTF values are up to
0.6 plus. The technical requirements of high-precision, small size, light weight, good image quality are fulfilled.
OTF reflects the frequency characteristic of optical system and is the key parameter that evaluates the imaging
quality of aerospace optical lens. The aspherics make the optical system simplified in structure with the imaging
quality assured at the mean time, however the assembling technology of aspheric optical system is restricted
because the fabrication technology is difficult and a lack of testing means. In this paper, means of OTF testing is
adopted and a testing frock clamp is designed and processed to test the OTF of aspherics during its fabrication, and
the result of test is used to supervise the fabrication until meet its target. During the assembling of the aspheric lens,
the source of aberration that affects the imaging, which is used to supervise the next assembling, is analyzed
according to the test result of OTF instrument, and test the OTF of re-assembling aspheric lens another time to see
whether the result is meet the request, then the assembling will be accomplished. The result of experiment shows
that it is feasible to supervise the fabrication and assembling of aspheric optical system by OTF instrument.