Concave lenses

FIGURE 5.8 (a) CARS energy diagram, (b) Experimental setup BS, 15% beam splitter VA, variable attenuator A/2, half-waveplate Dl, 950 nm longpass dichroic mirror D2, 750 nm longpass dichroic mirror F, three 670 nm bandpass filters LI, aspheric lens L2, 10 cm concave lens. 

Lenses were known in ancient times, and by the fifteenth century their use in spectacles was common. It was not until the seventeenth century, however, that a convex and a concave lens were put together in a tube to form the first crude microscope. Galileo used one of the first instruments, and he was amazed to discover the compound eyes of insects. Stelluti... 

The temperature coefficient of refractive index is, for most liquids, negative, consequently, the insertion of a liquid in the laser beam produces a concave lens that results in beam divergence. 

When a certain small separation, h, the inversion thickness, is reached, the sign of the curvature in the contact of the fluid particles (drops, bubbles) changes. A concave lens-shaped formation called a dimple is formed (see Frankel and Mysels" ). This stage is also observed for asymmetric fllms." A number of theoretical studies have described the development of a dimple at the initial stage of film thinning The inversion thickness can be calculated from a simple equation in which the van der Waals interaction is explicitly taken into account (see Section 5.4.2)i 4,43i,465... 

A frequent trouble encountered in spectrophotometric readouts is the generation of spurious peaks due to differences in refractive properties of the sample and car-rier/reagent. In case of a substantial difference in the refiractive index, the parabolic interfaces at the two ends of the sample zone create convex and concave lens effects on... 

Elliott and Wedgwood (1964) and Kasuya (1966) studied the effect of band splitting on x(9) using an imperfect nesting Fermi surface model which was derived from a spherical Fermi surface model. For a trivalent metal with a spherical Fermi surface, the surface extends outside the Brillouin zone in the c direction. When the pieces of the surface outside the zone are folded back into the first zone, there arises a surface in the shape of a concave lens as shown in... 

The focal point F of a concave lens is the point where parallel rays of light seem to originate (Figure 10.10 (middle)). As for convex lenses, a symmetric focal point F exists on the other side of the lens. 

The first set-up comprises two convex lenses L i and L2. Note that the forward focal point F of lens Li coincides with the rear focal point F2 of lens L2 see Figure 10.12 (top). This type of beam expander/ collimator is often called a Keplerian beam expander (its name is derived from the alleged inventor of the refracting telescope, which closely resembles the beam expander). The second method uses a combination of a concave lens Li followed by a convex lens... 

Negative Lens Concave lens with thick edges and a thinner center, used most often in eyeglasses for correcting nearsightedness. 

The minus/plus signs correspond to the convex/concave lens. 

Figure 2.21 Profilometry images of photoinduced microlenses produced in a GeAsSei3 glass, (a) Convex lens produced by photoexpansion on an annealed glass exposed to 5 W/cm light, (b) Concave lens produced in a quenched glass exposed to 0.4 W/cm light, (c) Combined concave-convex lens produced by subsequent irradiation at 0.4 W/cm and 3.5 W/cm with a focused beam. (After [87].]...

Actually, if ri (the initial polymer/homopolymer - the product of prepolymerization of gel-polymer) is greater than (the product of polymer-analogous transformation/diffusion copolymerization), then decrease of the process duration with the radius of the polymeric/gel-polymeric film/plate from its periphery to center gives a medium with properties of a convex lens and, vice versa, at the increase of the process duration with sample radius from periphery to center, a medium possessing properties of a concave lens may be obtained. 

The opposite results are obtained, when polymer-analogous transformation /diffusion copolymerization is accompanied by an increase of refractive index, i.e. when ri > 2 In this case, decrease of the process duration by the sample radius from the periphery to the center produces a medium with properties of a concave lens, and increase gives a medium with properties of a convex lens. In this process, the results mentioned are achieved under conditions of injection of an active medium/diffusate and an inert liquid into the reactor under different regimens. 

CX convex, CV concave. Lens 2 rear surface radius = 19.33884 CV, conic constant 1.711456, Ai = 1.0343xl0, Ae = 7.088xl0. Filter located between lenses 3 and 4. 

A concave lens cavity model with heater and cooling chaimels as shown in Fig.l were utilized for the simulation and experiment. The heater was put in the vicinity of the lens center, and the cooling chaimels were put around the cavity. Fig.2 is the cut view of the meshed cavity and coolant chaimel. The lens part is meshed by the hexahedral element, and the coolant chaimels are meshed via the combination of prismatic element in the axial direction and the tetrahedral element in the juncture region. The mold base is meshed by the tetrahedral element except in the region adjacent to the coolant surface, where only pyramid element can be used. 

---