Flat folding mirror

The OWL optical design is shown in Fig. 1. It is based on a spherical and flat folding secondary mirrors, with a four-element corrector providing for the compensation of spherical and field aberrations as well as advanced active optics and dual-conjugate adaptive optics. A complete discussion would exceed the scope of this report we shall however mention a few key arguments supporting this solution ... 

In the conics section we discussed the property of parabolas. Since one of its conjugates is at infinity, it will form a perfect image from the infinite conjugate at focus. This is the basis for a single mirror telescope. This telescope is either used at this prime focus, or sometimes a folding flat mirror (Newtonian telescope) is used to fold the beam to a convenient location for a camera or the... 

The standard 0.75 M Spectraspan III has an approximately 6 cm x 7.5 cm display. Since the CID used is only 1.1 x 0.85 cm, only a very small portion of this display could be observed at any one time. However, this problem has been recently reduced by substituting a 15 cm focal length, f/1.4 Schmidt corrected Cassegrain telescope (Nye Optical, Spring Valley, CA) for the camera mirror (Figure 3). This reduces the display dimensions five fold. The focal plane remains flat and a minimum resolution of 0.1 nM is achieved. With this optical system the entire 200 to 800 nM region cannot be viewed simultaneously. Further image reduction is possible, but resolution will be compromised... 

Figure4.8 shows the collecting telescopes configuration. Each consists of a pair of focal parabolas (primary Ml, secondary M2) used in a Cassegrain configuration, plus a fold flat used for coarse beam steering (M3). The design is based in NASA s SPIRIT proposal (Wilson et al. 2007). After the beam steering mirror the light is...

The HeNe laser passes at a distance of 0.7 mm over the heated region, i.e. above the focus of the CO2 laser, employing several times a flat mirror multiple pass system it consists of two square flat mirrors (flatness X/20 Melles Griot) with highly reflective MAXBRIte coatings (R = 99.5%), tilted with respect to each other by a small angle 0. In our actual experiments, the number of passes is 31 with 0 1° and a mirror distance of about 40 mm. The number of passes not only leads to an enhanced total deflection angle, but also increases the lever arm to the detector (de Vries et al. 1992) therefore, 31 passes lead to a 300-fold deflection as measured by the PSD. 

The gain volume is at the focal point of a folded cavity, consisting of two spherical mirrors and a flat output coupler. Tuning is accomplished with a birefringent, so-called Lyot filter [8.71]. This consists of one or several crystalline quartz plates mounted at the Brewster angle. The dominant transmission maximum of this filter can be moved by turning the optical axis of the filter with respect to the plane of polarization of the light in the... 

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