A fast and simple solution is proposed to wavefront sensing for laser beams with spatial smoothly varying intensity, where Shack–Hartmann wavefront sensor and the modified Fourier domain centroiding algorithm are applied. Detailed analysis has been conducted to Fourier domain centroiding, simplifying the origin double-frame method to work with merely single frame, and revealing its interesting property of robustness to nonuniform intensity perturbation. The key parameter is also analyzed to optimize the algorithm’s performance. Numerical simulations demonstrate that the proposed method outperforms the center of gravity algorithm, with an average phase error reduction up to approximately one order in root mean square. Application of the proposed method in joint amplitude–phase compensation system is also verified by simulation with practical models and parameters. The modified Fourier domain centroiding is promising to enhance real-time actual wavefront measurement for adaptive optics in high-power lasers, such as joint amplitude–phase compensation.
Photodynamic diagnosis (PDD) is of increasing interest for diagnosis in oncology. It is based on the selective
accumulation of photosensitizers in tumours, such as porphyrin and phthalocyanine. In the present study, novel
dihydroxy phosphorus tetrabenzotriazacorrole derivates have been synthesized. And photophysical properties of these
derivates have been studied. Dihydroxy phosphorus tetrabenzotriazacorrole derivates display a fluorescence which is
from the higher S2 electronic state. With excitation at 614 nm, the fluorescence maximum is at 668 nm for dihydroxy
phosphorus(V)-2,9,16,23-tetranitrotetrabenzotriazacorrole {P(OH)2TBC(NO2)4} in N,N-dimethylformamide (DMF). But
with excitation at 310 nm for P(OH)2TBC(NO2)4 in DMF, in addition to S1 fluorescence a new fluorescence peak
appears at 490 nm, which is attributed to S2-state fluorescence. It indicates that the dihydroxy phosphorus
tetrabenzotriazacorrole derivates might have a potential application as a dual fluorescent marker for photodynamic
diagnosis.
Phthalocyanine materials have successfully been applied in infrared ray optical disc systems. Seeking for the phthalocyanine-analogous materials with great conjugate macrocyclic π bond system is the key for new materials research of super high density blue laser optical storage. Dibenzotetraaza [14] annulene have the similar macrocyclic structure. It was used as a building block for the preparation of multi-component materials matched the requirement of recordable blue laser optical disc. Ester substituents have been generated with oxalyl dichloride (or phosgene) and appropriate HO-function-containing substrates. A range of new complexes equipped with ester groups derived from various alcohols and phenols have been prepared. The new products have been characterized by UV-Vis spectrometer, TGA, refractive index of the organic films. These kinds of materials have suitable light and thermal sensitivity, and it is a valuable material for blue laser optical storage.
In this paper, the pupil energy distribution is calculated with parameters of digital versatile disk and by using the scalar diffraction theory. In view of radial tilt, a radial tilt angle in pit model is added, and consequently, a simulation of push-pull tracking error is given when a radial tilt error occurs. Furthermore, the influence of radial tilt is analyzed by using push-pull tracking servo method.
As excellent performance is difficult to achieve in traditional laser beam scanner, which adopt cumbersome transmission mechanisms, this paper will propose a novel type, which employs permanent magnetic suspension structure. Static stability of such a scanning system will be analyzed fully based on magnetic theory and 3D-FEM tools. Finally, typical experiments verify that high static stability can be realized by this novel permanent magnetic suspension scanner. Other techniques involved in this type of laser beam scanner, including the scanning theory, precision control and dynamic stability, will be referred in later papers.
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