Folding mirror

Figure 2. Schematic drawing of a control apparatus. A laser of frequency coi is focused by lens L into a cell containing a tripling medium such as Hg vapor. Mirrors Ml and M2 are mounted inside a phase tuning cell (not shown) containing a refractive medium such as H2. The folded mirror geometry produces a pair of elliptical astigmatic foci, one of which overlaps the molecular beam (MB) at a distance zm from the beam axis. (Reproduced with permission from Ref. 62, Copyright 2006 American Physical Society.)...

The twofold mirror-rotation axis is the simplest among the mirror-rotation axes. There are also axes of fourfold mirror-rotation, sixfold mirror-rotation, and so on. Generally speaking, a 2 -fold mirror-rotation axis consists of the following operations a rotation by (360/2//) and a reflection through the plane perpendicular to the rotation axis. The symmetry of the snowflake involves this type of mirror-rotation axis. The snowflake obviously has a center of symmetry. The symmetry class m-6 m contains a center of symmetry at the intersection of the six-fold rotation axis and the perpendicular symmetry plane. In general, for all m n m symmetry classes with n even, the point of intersection of the //-fold rotation axis and the perpendicular symmetry plane is also a center of symmetry. When n is odd in an m-n m symmetry class, however, there is no center of symmetry present. 

A frequency-doubled Nd YAG (neodymium yittrium aluminum garnek) laser was used to provide excitation at 532 nm. A high-speed silicon photodiode views the radiation scattered from the first folding mirror to... 

Fig. 10.8 Thin-layer electrochemical cell used in SNIFTIR studies and reflection optics (a) Teflon cap (b) N2 inlet (c) glass tube (d) Teflon cell body (e) port for reference electrode (f) ceramic tube (g) Pt wire counter electrode (h) single crystal working electrode (i) hemispherical ZnSe window (k) focal plane for reflection optics (m) instrument focal plane and (n) folding mirrors (From reference 16, with permission.)...

A molecule may be symmetric. This symmetry, through its centre point, is referred to as its point symmetry. This symmetry may be invariant to rotation axes (2,3,4,5,6,7 etc fold), mirror planes, inversion centres or a combination of these. 

The maximum incident pump power was 3.97 W. The folding mirrors, i.e., Ml and M2, had a 100 mm radius of curvature (ROC) and AR-coated below 1000 nm and HR-coated above 1020 nm. The laser beam was focused onto a semiconductor saturable absorption mirror (SESAM) by a concave mirror M3 with ROC = 50 mm. The chirped mirror pair, i.e., CMl and CM2, had a group-delay dispersion of -2000 fs per one round trip. The OC had a 1 % transmittance. 

A variation of the same optical system, as shown in Figure 4-14, is used in the Consolidated Electrodynamics direct reading spectrometers. The optical system is folded, with the use of a folding mirror, to make the instrument more compact. Using a 30,000 lines/in. grating provides a linear reciprocal diversion of about 2.78 A/mm. Spectral intensities are determined by using photomultiplier tubes mounted at the exit slits. 

The dye laser was fully optimized for these fundamental tuning curves, making the available input power be the limit to the output reached. With the weaker pump lines, the radius of the fold mirror (Ml of Fig. 10) was decreased to tighten the dye and matching pump focal areas and keep the gain well above the 2.5% s.f. cavity losses. (The 10-cm radius for the red dyes became 7.5 cm for the stilbenes, coumarins, and S9M, and 5.0 cm for IR140). The transmission of the output coupler was also optimized across the span of each dye (the breaks on several of the tuning curves are places where a different output coupler was... 

The fluorescence is spectrally resolved by a grating and spatially separated by three slightly folded mirrors, which image a cancer region and a region of normal cells onto different parts of the diode array of an optical multichannel analyzer (Sect. 4.5). A computer subtracts the fluorescence of the normal tissue from that of a cancerous tissue. 

In determining final display luminance, transmission, reflectance, and scattering by additional optical elements such as dichroic filters, optical-path folding mirrors, or corrective lenses must also be accounted... 

In order to achieve a symmetric beam waist profile of the dye laser mode in the active medium, the astigmatism produced by the spherical folding mirror M3 in the folded cavity design has to be compensated by the plane-parallel liquid slab of the dye jet, which is tilted under the Brewster angle against the... 

Figure 3.5 HR-CS AAS setup with DEMON spectrometer (1 xenon short-arc lamp, 2 hollow cathode lamp (optional), 3 elliptical mirrors, 4 atomizer, 5 entrance sUt, 6 parabolic minors, 7 prism, 8 folding mirrors and intermediate sht, 9 echelle grating, 10 CCD detector)... 

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