Concave mirrors

Several LED chips have been mounted together on the same thermoelectric cooler shown in Fig. 13.56b. This nondispersive IR analyzer utilizes sample and reference PbSe photoresistors as detecting elements. The LED emission (4.3 xm for CO2 and 4.7 xm for CO detection) is focused onto a sample photodetector by a concave mirror. 

Hohl-schicht,/. air space, -spat, m. chiastolite. -spiegel, m. concave mirror, -tiere, n.pl. (Zodl.) Coelenterata. 

Konkavspiegel, m. concave mirror. Konkrement, n. concrement, concretion, konkret, a. concrete. 

The relationships in Figure 4-11 are strongly reminiscent of those that exist for ordinary light diffracted from a concave Rowland grating.24 To understand this process, it is best to look first at the reflection of light from a concave mirror. 

Figure 3. Optical system of instrument of spectral sensitivity measurement (L) Xe arc lamp (Ml) concave mirror (M2, M3) mirror (S) shutter (SI) slit (G) concave reflective grating...

Figure 24.8 Experimental schematic of the multiplexed diode-laser sensor system used to measure CO, CO2, CH4, and H2O absorption by sampling hot combustion gases 1 ECDL 1.49-1.58 pm 2 optical isolator 3 — fiber coupler 4 — 1x2 fiber splitter 5 — etalon 6 — InGaAs detector 7 — DEB 1.65 pm 8 — 2 x 1 fiber combiner 9 optical fiber 10 fiber pitch 11 — concave mirror 12 — multipass...

Atomic emission from the plasma is focused on to the entrance slit of the monochromator using a combination of convex or plano-convex lenses or a concave mirror. The combination of focusing optics, monochromator and detector is generally referred to as a spectrometer, although the heart of the device is the monochromator. A monochromator is an instrument that... 

C. Infrored (IR) Guidance System condisted essentially of a concave mirror directed toward a target emitting the infrared radiation. 

Experiments were performed using a titanium sapphire laser oscillator capable of producing pulses with bandwidths up to 80 nm FWHM. The output of the oscillator was evaluated to make sure there were no changes in the spectrum across the beam and was compressed with a double prism pair arrangement. The pulse shaper uses prisms as the dispersive elements, two cylindrical concave mirrors, and a spatial light modulator (CRI Inc. SLM-256), composed of two 128-pixel liquid crystal masks in series. The SLM was placed at the Fourier plane [5]. After compression and pulse shaping, 200 pJ pulses were used to interrogate the samples. 

Rowland was the first to rule reflection gratings on concave metal surfaces. Such gratings eliminate the necessity of the spectroscope collimator or focusing lenses, as they take light direct front the spectroscope slit and form the spectral-line images like a concave mirror. The echelon is another special type of grating. 

Focusing the 27th Harmonic Beam Using a SiC/Mg-coated Concave Mirror... 

Fig. 9.7. Focused beam spot size of the 27th harmonic wave as a function of distance from the SiC/Mg multilayer coated concave mirror. The open circles and filled squares correspond to the horizontal and vertical directions respectively. The best-fit curves based on (9.1) are also shown by the solid lines...

In the same way, the 13th harmonic beam at 61 nm was selected by a tin-foil filter and focused by a SiC concave mirror with a focal length of 50 mm. The angle of incidence was set at 7 degrees. Figure 9.9 shows the 1/e2 beam spot size of the 13th beam as a function of distance from the concave mirror. The... 

For a concave mirror of radius of curvature R (Fig. 2.16) a point object at a distance u from the mirror forms a real image at a distance v from the mirror,... 

A spherical concave mirror of radius R — CP = CQ reflects an object at O (mirror-object distance OP = u) into image at / (mirror-image distance IP= v). If object moves to infinity (u = oo), then all rays from that object will converge at the principal focus point F f—FP = (1/2) CP—RI2] that is, the principal focal length f is half of the radius of curvature. 

The most important and unique part of a Fourier transform microwave spectrometer is the Fabry Perot cavity. A fairly complete description of the principles has been given by Balle and Flygare [14] and we here summarise the main aspects, with the aid of figure 10.19. We use the cavity built by Balle and Flygare as a typical example. It is formed by two parallel, spherical concave mirrors made from solid aluminium. The mirrors are 36 cm in diameter, have a radius of curvature (R) of 84 cm, and are situated... 

For DRIFT studies, a wood wafer, paper sheet, or milled wood sample dispersed in KBr (or KC1) is placed in a cup at the focal point of the concave, ellipsoidal mirror so that the incident light is focused on the sample. The scattered light coming from the sample is collected from the concave mirror and directed by a suitable mirror system to the detector of the FTIR instrument. The pressure used for smoothing the sample has to be adjusted so that reproducible results can be obtained (Yeboah et al. 1984). The contribution of specular reflectance can be diminished by reducing the particle size and by increasing the sample dilution. For powder samples, as indicated above, the diluent is KBr or KCI. Good results are normally obtained with alkali halide powders that contain 1-2% of sample. In certain cases, the sample concentration may be increased up to 10%. 

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