The generalized Coddington equations from caustic theory, the Abbe sine condition, and the constant optical path length condition have been used to design two-mirror microscope systems. These two-microscope systems ar...
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ISBN:
(纸本)0819418994
The generalized Coddington equations from caustic theory, the Abbe sine condition, and the constant optical path length condition have been used to design two-mirror microscope systems. These two-microscope systems are free of two of the three aberrations - spherical aberration, coma, or astigmatism, depending on which two of the three design conditions are used. The optical performance of the resulting two-microscope systems has been compared to that of the Schwarzschild microscope and the Head microscope. The goal of this study is to identify design methods for reflective systems which will yield diffraction limited performance for large numerical apertures and fields of view. Also, these design methods are being extended to a three-mirror telescope.
This study investigates the effects of changing the flint glass of a Cooke triplet from the optimum glass type, in an attempt to determine how many different glass types are necessary. To this end, about 90 triplets w...
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ISBN:
(纸本)0819418994
This study investigates the effects of changing the flint glass of a Cooke triplet from the optimum glass type, in an attempt to determine how many different glass types are necessary. To this end, about 90 triplets were designed, each with a flint glass displaced from its optimum characteristics. Sixteen different combinations of field and aperture, and three different crown glass types were used. variations of performance with flint changes are presented. An 'acceptable' variation of the flint glass v-value appears to be about plus or minus 2.
The case study of a rotation detector was used to illustrate design employing optical components. The device must detect the rotation of a disk with a small hole, in the presence of sunlight entering the building and ...
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The case study of a rotation detector was used to illustrate design employing optical components. The device must detect the rotation of a disk with a small hole, in the presence of sunlight entering the building and light emitted by incandescent and fluorescent lights, which provide light with a 100Hz modulation. The power available is 6 mA at 12 v. The shaft can rotate at speeds of up to 100 rpm. The rotation detector can be created by aligning the LED and detector so that hole in the wheel causes a current in the detector. The received signal was estimated and the direction of shaft rotation was detected.
Germanium (Ge) is the most widely used material in long wave infrared (LWIR) refractive telescopes due to its high index of refraction and very low dispersion characteristics. Unfortunately, germanium's absorption...
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ISBN:
(纸本)0819418994
Germanium (Ge) is the most widely used material in long wave infrared (LWIR) refractive telescopes due to its high index of refraction and very low dispersion characteristics. Unfortunately, germanium's absorption increases dramatically when operating in hot environments. Traditionally, the operating temperature of Ge is extended by doping to reduce the absorption coefficient's temperature dependence. However, depending upon the opticaldesign form, transmission losses attributed to an operating temperature rise of 40 degrees, may still be as high as 5 to 15 percent. When such absorption losses are not tolerable, alternative materials such as ZnSe, Amtirl, and GaAs can be considered. In this paper a series of case studied is presented to compare the predicted performance of conventional Ge dominated designs with lenses composed almost entirely of these alternative materials. Fabrication and production cost issues are compared along with the utilization of hybrid refractive/diffractive optical elements.
The incorporation of abnormal dispersion liquids into an opticaldesign can result in significant performance advantages. However, the large thermal coefficient of refractive index which is common to all liquids (dn/d...
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ISBN:
(纸本)0819418994
The incorporation of abnormal dispersion liquids into an opticaldesign can result in significant performance advantages. However, the large thermal coefficient of refractive index which is common to all liquids (dn/dT) can complicate the athermalization of these designs. One method is to use two different liquids to form both positive and negative liquid lens elements which balance each other thermally while maintaining color correction. The success of this approach is dependent on the proper selection of materials, and on a detailed knowledge of the wavelength dependence of the refractive index thermal coefficients. The thermal dependence of refractive index and dispersion in the visible spectral region for a number of liquids was investigated. A correlation between the refractive index thermal coefficient (dn/dT) and abnormal dispersion was found to exist in a majority of liquids. The optical property measurements were made at the vavilov State optical Institute, St. Petersburg, Russia in collaboration with the Lockheed Palo Alto Research Laboratory, Palo Alto, California.
In this article we have designed a new type of prismatic telescope which can be used to amplify the divergence of the laser beam. Theoretical analysis and computer analog indicate that the divergence multiplication fa...
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ISBN:
(纸本)0819418994
In this article we have designed a new type of prismatic telescope which can be used to amplify the divergence of the laser beam. Theoretical analysis and computer analog indicate that the divergence multiplication factor is independent of the distance between the prismatic telescope and the waist of the laser beam, and the original divergence of the laser beam in 20 mrad, the laser beam as it passes through the prismatic telescope is still Gaussian beam. We have made and measured the prismatic telescope and found the result agrees with our theoretical analysis.
Recently the laser microbeam instrument has been used for wider applications in biological science and medicine. A key problem of the laser microbeam instrument is designing the laser focusing system for getting a foc...
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ISBN:
(纸本)0819418994
Recently the laser microbeam instrument has been used for wider applications in biological science and medicine. A key problem of the laser microbeam instrument is designing the laser focusing system for getting a focal spot size of less than 1 micrometer. This paper presents a new laser focusing system which is composed of a spatial filter and an 80× focusing objective lens. The 80× focusing objective lens was designed as a double reflective sphere type. Using this focusing system, the laser microbeam instrument has gotten a focal spot size of less than 0.5 - 1 micrometer. The focal spot size depends on the pinhole diaphragm diameter of the spatial filter. Different pinhole diaphragm diameters could produce different focal spots that are given in the end of this paper.
Recent developments of stability control in mines, essentially based on Ge-doped Fiber Bragg Gratings (FBG) are reported including results about the different aspects of the system: accurate characterizations of FBG, ...
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Recent developments of stability control in mines, essentially based on Ge-doped Fiber Bragg Gratings (FBG) are reported including results about the different aspects of the system: accurate characterizations of FBG, sensor network topology and multiplexing method, user interface design and sensor packaging.
The effect of shunt-shunt feedback in monolithic transimpedance amplifiers for multiGbit per second optical receivers on the input impedance is considered in this paper. The main transfer function to be optimized is t...
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ISBN:
(纸本)0819417483
The effect of shunt-shunt feedback in monolithic transimpedance amplifiers for multiGbit per second optical receivers on the input impedance is considered in this paper. The main transfer function to be optimized is the transimpedance, but the input impedance should be taken into careful consideration to avoid unexpected peaking effects which can be a cause of performance degradation. The interconnection technique used to couple the photodiode to the MMIC amplifier has to be properly chosen in conjunction with the performance of the amplifier as current sink at the input port. We propose a design methodology based on the root-locus technique which can help the designer in the optimization of this kind of circuit with particular regard to the input peaking effects.
Charge-coupled devices have found widespread use in many imaging applications and demonstrate many advantages over other detector technologies such as high speed, low power, low noise, and small physical size. Neverth...
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ISBN:
(纸本)0819417629
Charge-coupled devices have found widespread use in many imaging applications and demonstrate many advantages over other detector technologies such as high speed, low power, low noise, and small physical size. Nevertheless, `off-the-shelf' CCD architectures are frequently not feasible for many unique applications, requiring custom CCD designs and processing. In this paper the authors discuss a CCD sensor developed specifically for a near- infrared linescan-type application. The authors discuss the architecture, design, and performance of the sensor, as well as current work in the project.
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