Optical transfer

Within this work [7] a method and model to determine the optical transfer function (OTF) for the detector chain without detailed knowledge of the internal detector and camera characteristics was developed. The expected value of the signal S0.2 is calculated with... 

Abstract This is a tutorial about the main optical properties of the Earth atmosphere as it affects incoming radiation from astrophysical sources. Turbulence is a random process, of which statitical moments are described relying on the Kolmogorov model. The phase structure function and the Fried parameter ro are introduced. Analytical expressions of the degradation of the optical transfer function due to the turbulence, and the resulting Strehl ratio and anisoplanatism are derived. 

The Optical Transfer Function (OTF) is related to the phase stmcture function as follows (Roddier,1981)... 

Where thermal electron transfer can occur, there is also always a corresponding optical transfer, which I have termed intervalence transfer (19-21). The principle is illustrated in a single coordinate representation in Figure 2. Clearly, it will be possible to relate thermal to optical transfer probabilities, and, hence, to predict the rate of one process from parameters obtained for the others. The connection is, in fact, a very close one, as indicated schematically in Figure 3. 

Does T differ significantly from unity in typical electron transfer reactions It is difficult to get direct evidence for nuclear tunnelling from rate measurements except at very low temperatures in certain systems. Nuclear tunnelling is a consequence of the quantum nature of oscillators involved in the process. For the corresponding optical transfer, it is easy to see this property when one measures the temperature dependence of the intervalence band profile in a dynamically-trapped mixed-valence system. The second moment of the band,... 

Hashimoto, M., and Araki, T. 2001. Three dimensional coherent and optical transfer functions of coherent anti-stokes Raman scattering microscopy. J. Opt. Soc. Am. A 18 771-76. 

Heygster, G., Block, H., Gadomski, A., and Boseck, S. (1990). Modeling of the optical transfer function (OTF) of the scanning acoustic microscope (SAM) and its relation to the other scanning microscopes. Optik 85,89-98. [28, 200]... 

The factor 1.22 in Eq. 2.1 was empirically derived by Rayleigh. It may be derived from the radius of the circle, known as the Airy disk, from the optical transfer function. In 1873, the German physicist Ernst Karl Abbe (1840-1905) showed that the numerical... 

Another way to achieve the reading data with RCM is to use the multilayered recording medium in which photosensitive thin films and nonphotosensitive transparent films are alternately stacked. Since the photosensitive films are thinner than the depth of focus of the recording beam, the spatial-frequency distribution of the recorded-bit data is extended in the axial direction. The extended distribution overlaps the coherent optical transfer function of the RCM. 

Figure 16.19 shows the spatial-frequency distributions of bit data recorded with focused laser beam and coherent optical transfer function (CTF) of reflection type confocal microscopeFigure 16.19a shows a spatial-frequency distribution of bit datum recorded in very thick medium. This distribution coincides with the spatial-frequency distribution of the focused light to record the bit datum, because the bit is recorded with the focused beam. It is assumed that the NA of the objective lens is given by n sin a and k =l ulk, where A denotes the wavelength. 

An alternative readout system is a scanning differential phase-contrast microscope with a split detector as shown in Figure 16.5. The optical configuration is compact and easy to align. The memory medium, in which the data bits have been recorded, is located at the focus of an objective lens. The band limit of the optical transfer function (OTF) is the same as that of a conventional microscope with incoherent illumination. The resolution, especially the axial resolution of the phase-contrast microscope, is similar to that obtained by Zemike s phase-contrast microscope. The contrast of the image is much improved compared to that of Zernike s phase-contrast microscope, however, because the nondiffracted components are completely eliminated by the subtraction of signals between two detectors. The readout system is therefore sensitive to small phase changes. 

Although the above method of calculating the reflectivity can be extended to multilayer systems with any number of discrete layers, it becomes unwieldy as soon as the number of layers involved exceeds four or five. A computationally more efficient method is offered by the use of an optical transfer matrix. Here we simply summarize the method as described by Lekner.6 For any single layer j within the multilayer... 

K. Winkler, F. Lang, G. Thalhammer, P.v.d. Straten, R. Grimm, J. Hecker Denschlag, Coherent optical transfer of Feshbach molecules to a lower vibrational state. Phys. Rev. Lett. 98,043201 (2007). cond-mat/0611222... 

Measured Performance. Under the conditions of space invariance and incoherence, an image can be expressed as the convolution of the object irradiance and the point-spread function, Eq. (26.15). The corresponding statement in the spatial frequency domain, Eq.(26.28), is obtained by taking the Fourier transform of Eq. (26.15). This states that the frequency spectrum of the image irradiance equals the product of the frequency spectrum of the object irradiance distribution and the transform of the point-spread function. In this manner, optical elements functioning as linear operators transform a sinusoidal input into an undistorted sinusoidal output [Eq. (26.33)]. Hence the function that performs this service is the transform of the point-spread function 3 A(x, y), known as the optical transfer function 0 u, v] (OTF). This is a spatial frequency-dependent complex function with a modulus component called the modulation tranter function M u. v] (MTF) and a phase component called the phase tranfer function 4>[ , v] (PTF). The MTF is the ratio of image-to-object modulation, while the PTF is a measure of the relative positional shift from object to image. 

The optical transfer function (OTF) presents the fineness with which we can transmit spatial information in the spatial frequency domain. The OTF H s) is defined with s the spatial frequency. 

Optical transfer function Function measuring the complex amplitude of the image transmitted by an optical system illuminated by a unit-amplitude sinusoidal pattern, versus the spatial frequency. 

FIGURE 12 Optical transfer functions related to incoherent illumination of square (left) and round (right) pupils. T is proportional to the convolution of the pupil function [see top diagram and Eq. (45).]... 

---