Angular acceptance

Bulk potassium niobate (KNbOs) is well suited to our needs, beeause birefringent type-I non-critical phasematehing (NCPM) can be exploited for highly efficient SHG of 850 nm at room temperature . This NCPM avoids any spatial waUc-off between the fundamental and second harmonic beams, as well as maximizing the angular acceptance of the phasematching process. 

Finally we remark that proper alignment of all diffractive-optic beam corrditioners normally reqrrires that they be adjusted with a common dispersion plane. This is defirred as the plane corrtaining the incident and diffracted beam (and therefore also the rrormals of the diffracting plane) for any given reflection. If the dispersion planes are rrot parallel then some intensity will be lost from the restriction this causes to the angular acceptance in the plane perpendicular to the dispersion plane. 

In this chapter we show how restricting the angular acceptance of the detector adds another dimension to the information available from high resolution diffraction techniques, enabling strains and tilts in a sample to be identified separately. We explain the reciprocal space representation of triple-axis diffraction maps, and give several examples of its application to materials characterisation. 

RFA), which, though having a poorer energy resolution than the PPA had the virtue of a wider angular acceptance for scattered particles. 

The diffraction experiments can be performed on the same Kretschmann SPR set-up (cf. Fig. 6). To resolve the diffraction orders, the angular acceptance of the photo-diode detector is defined by a 1 mm slit to be At 0.08°. The coaxial goniometers enable an independent tuning of the incident angle of the laser and/or the detection angle. Both motors rotate in a 0/20 fashion for the usual SPR angular scans, whereas only the detector motor rotates when performing diffraction scans. 

In spectromicroscopy, one encounters an even smaller etendue. One can investigate a sample area of as small as 3 pm2, with an angular acceptance of 0.7 rad (41°) has an etendue of ... 

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