Diameter Of Microlens Research Articles

Fabrication of multilayer systems combining microfluidic and microoptical elements for fluorescence detection

This paper presents the fabrication of a microchemical chip for the detection of fluorescence species in microfluidics. The microfluidic network is wet-etched in a Borofloat 33 (Pyrex) glass wafer and sealed by means of a second wafer. Unlike other similar chemical systems, the detection system is realized with the help of microfabrication techniques and directly deposited on both sides of the microchemical chip. The detection system is composed of the combination of refractive microlens arrays and chromium aperture arrays. The microfluidic channels are 60 /spl mu/m wide and 25 /spl mu/m deep. The utilization of elliptical microlens arrays to reduce aberration effects and the integration of an intermediate (between the two bonded wafers) aluminum aperture array are also presented. The elliptical microlenses have a major axis of 400 /spl mu/m and a minor axis of 350 /spl mu/m. The circular microlens diameters range from 280 to 300 /spl mu/m. The apertures deposited on the outer chip surfaces are etched in a 3000-/spl Aring/-thick chromium layer, whereas the intermediate aperture layer is etched in a 1000-/spl Aring/-thick aluminum layer. The overall thickness of this microchemical system is less than 1.6 mm. The wet-etching process and new bonding procedures are discussed. Moreover, we present the successful detection of a 10-nM Cy5 solution with a signal-to-noise ratio (SNR) of 21 dB by means of this system.

Modeling of the microlens fabrication in glasses by field-assisted ion exchange: The space charge effects

Effects of the space charge on the microlens formation in glasses using the electric-field-assisted ion exchange process have been analyzed by numerical methods. It is shown that the electric field strength in the substrate is inhomogeneously distributed and decreases with time. Since the field-assisted migration velocity depends on the field strength, these factors slow down the ion exchange rate and decrease the microlens diameter below the values calculated assuming a homogeneous field strength distribution in the substrate.

Optical Properties of Homogeneously- and Hibrid-Aligned Liquid Crystal Microlenses

Optical properties of homogeneously- and hibrid-aligned liquid crystal (LC) microlenses with positive dielectric anisotropy have been researched. Focal distance-voltage dependencies have been obtained. When voltage is low the microlenses possess focusing optical properties. The focal distance is decreased with voltage increasing then it reaches a minimal value and is increased. At higher voltage defocusing optical properties are observed. The microlens focal distance decreases approximating asimptotically to the certain value. The focal length increase with microlens diameter and it is longer for hibrid-aligned LC-microlens compared to homogeneously-aligned one. The results of experiments agree qualitatively with the results of [1–3].

Wavelength-division microlens interconnection using weakly diffracted Gaussian beam

Free-space digital optics is a new technology that exploits the ability of optics to handle thousands of light beams or information channels at once. This and other features of optics complement the strengths and weaknesses of purely electronic systems. A compact free-space optical system is proposed that uses an array of microlenses for chip-to-chip and board-to-board interconnections. Here the weakly diffracted Gaussian beam and wavelength-division architecture are utilized to improve the channel density and reduce crosstalk in a microlens interconnection system. Based on the simulation, we improve the channel capacity by 3.47 times (or reduce crosstalk by 93.1 dB) while maintaining the same crosstalk (or channel density) compared with the conventional microlens interconnection system. The nonperfect filtering effect of different wavelengths at the detector plane is also studied to fully investigate the properties of the proposed scheme. The parameter sensitivity of the proposed system is studied for completeness. From the simulations, the relationship between the interconnection distance and spot size at the detector plane is wavelength-independent. In addition, the spot size is more sensitive to change of microlens diameter than to other system parameters.