Fraunhofer IPMS has developed a one-dimensional high-speed spatial light modulator in cooperation with Micronic Mydata AB. This SLM is the core element of the Swedish company's new LDI 5sp series of Laser-Direct-Imaging systems optimized for processing of advanced substrates for semiconductor packaging. This paper reports on design, technology, characterization and application results of the new SLM. With a resolution of 8192 pixels that can be modulated in the MHz range and the capability to generate intensity gray-levels instantly without time multiplexing, the SLM is applicable also in many other fields, wherever modulation of ultraviolet light needs to be combined with high throughput and high precision.
Nowadays novel micro-fabrication and wafer-based manufacturing approach allows realizing micro-optics in a way scientists have dreamt for generations, in particular, utilizing nano-imprint lithography as fabrication tooling enables greatly accelerating the micro-optics technology to its frontier. In this report, we present wafer-scale fabrication of various types of micro-optical elements based on photoresist, benzocyclobutene, photocurable imprint resist, and semiconductor materials by using thermal reflow, reactive ion etching, and imprint techniques. Especially, several concave or convex 3-dimensional micro-optical structures shaped by imprint method are detailed. These micro-optical elements can be monolithically or hybrid integrated onto optoelectronics devices, such as photodetectors and emitters as optical beam focuser, collimator, filter, or anti-reflectance elements. As application examples, polymer microlenses were integrated directly on the top of UV dual functional devices and quantum dot long wavelength infrared photodetectors, respectively.
A simple model for determining the amount of spectral broadening in acoustic sounder echoes caused by winds traveling perpendicular to the antenna beam is presented. Key features of the model are that the wind profile is described by an analytic function and the antenna radiation pattern is included in the calculations. The model was restricted to the situation where the antenna was aligned in the vertical direction and the winds were horizontal. The effects of refraction by temperature and wind velocity gradients were neglected. The radiation pattern used in the model was the sinc() or sin()/ function. The wind profiles which were used were a constant windspeed between the antenna and the scattering height, a profile where the windspeed increases linearly with height, and a logarithmic profile. Here, the amount of spectral broadening or spectral width of the echo is calculated by treating the amplitude spectrum of the echo as a probability distribution and determining the standard deviation of this distribution. It was found that the relationship between the standard deviation of the echo, , and windspeed, u, was closely described by a linear relationship, ϭBu, with the value of B ranging from 0.05 to 0.08 for the situations modeled here. Observational data are presented. The data were obtained with a sounder whose radiation pattern was approximated with the sinc function. The observed relationship between , and u, was essentially linear, agreeing favorably with the model predictions; however, the value of the proportionality constant B was 0.04. A possible explanation for this is that the radiation pattern for the antenna may have been underestimated since the effects of the sound absorbing shielding surrounding the antenna are unknown.
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