Microlen

The microgravitation lens (microlens) method Astronomical measurements... 

S M oiler and SR Forrest, Improved light out-coupling in organic light emitting diodes employing ordered microlens arrays, J. Appl. Phys., 91 3324-3327, 2001. 

Kobayashi, M., Fnjita, K., Kaneko, T., et al. 2002. Second harmonic generation microscope with microlens array scaimer. Opt. Lett. 27 1324. 

Tuning of the pre-tilt angle at the interface was also demonstrated by doping commonly used polyimide alignment layers with POSS nanoparticles [339]. In addition, the fabrication of a tunable liquid crystal flat microlens was achieved by placing a drop of a nematic liquid crystal doped with POSS nanoparticles onto a substrate inducing planar alignment (local HAN mode) [340]. Simultaneously, Takatoh and co-workers extended this concept to a series of metal oxide... 

M. C. Hutley, Microlens Arrays (Institution of Physics, Teddington, 1991). 

FIGURE 7.7 Cross-sectional view of a microchemical chip integrated with some optical components, (a) The microchemical chip showing the microlens (entrance and exit), the 3000-A Cr aperture layers (entrance and exit), and microchannel (25 pm deep) (b) the microchemical chip together with the pinhole (800 pm) and interference filter for detection by the photodetector [688]. Reprinted with permission from the American Chemical Society. 

Wu, H., Odom, T.W., Whitesides, G.M., Reduction photolithography using microlens arrays Applications in gray scale photolithography. Anal. Chem. 2002, 74(14), 3267-3273. 

In a somewhat similar fashion, Ishii et alP- have demonstrated inkjet fabrication of polymeric microlenses for optical chip packaging. UV curable epoxy resin is deposited onto optical devices by inkjet printing. When the droplets hit the surface, they form into partial spheres due to their surface tension, and are UV-cured to form the microlens with diameters from 20 to 40 tm with /-numbers of 1.0 to 11.0. Their uniformity in a microlens array was measured to be within 1% in diameter and 3 tm in pitch (total count of 36 lenses). They have also demonstrated hybrid integration of inkjetted microlenses with a wire-bonded vertical-cavity-surface-emitting laser (VCSEL) with coupling efficiencies of 4 dB higher than without the microlens. 

Risen and Wang developed a method and compositions for producing microlenses and optical filters. According to their method, carboxylated silicone or polysilicone precursor composition is applied to the surface of a substrate to form a precursor droplet, which is thermally oxidized to form a microlens. The substrates utilized were silica, silicates, borosilicate glasses, and silicones. The precursors, which are present in concentrated solutions, are viscous fluids which are used to form microdroplet precursors. A solvent such as ethanol or acetone is added to the precursors to modify and control their flow and surface tension properties, to facihtate the formation of spherical shape of the precursor on substrates. The precursor droplet volume is 4-600 picoliters and forms a droplet of 20 to 1000 micrometers in diameter. 

Biehl S, Danzebrink R, Oliveira P, Aegerter MA. (1998) Refractive microlens fabrication by inkjet process. / Sol-Gel Sci Tech 13 177-182. 

Peng H-, Ho Y.L., Yu X.-J., Wong M. and Kwok H.-S., Coupling Efficiency Enhancement in Organic Light-Emitting Devices Using Microlens Array-Theory and Experiment, /. Display Technol. 1 (2005) 278... 

J.-Y. Huang, Y.-S. Lu and J.A. Yeh, Self-assembled high NA microlens arrays using global dielectrophoretic energy wells. Optics Express, 14, 10779-10784 (2006). 

Kim J, Serpe MJ, Lyon LA (2005b) Photoswitchable microlens arrays. Angew Chem Int Ed 44 1333-1336... 

Optical fiber, microlens, slits, PMT detector Fluorescenin S/N = 3 [35]... 

Abstract Optical detection continues to dominate detection methods in microfluidics due to its noninvasive nature, easy coupling, rapid response, and high sensitivity. In this review, we summarize two aspects of recent developments in optical detection methods on microfluidic chips. The first aspect is free-space (off-chip) detection on the microchip, in which the conventional absorption, fluorescence, chemiluminescence, surface plasmon resonance, and surface enhanced Raman spectroscopies are involved. The second aspect is the optofluidic (inside-chip) detection. Various miniaturized optical components integrated on the microfluidic chip, such as waveguide, microlens, laser, and detectors are outlined. 

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