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2.1. Guide: locating feedback when no visible flashing occurs

This question predominantly arises for diodes with wavelengths greater than 1000nm where many cameras become insensitive and thus direct observation of the light is difficult. In this case we recommend the use of a power meter. In order to find a good starting point one can set the grating angle according to the wavelength, where the grating angle is defined between the collimator-/laser diode-holder (perpendicular to the beam) and the grating holder (front side on which the grating itself is mounted). In the table below the grating angle for selected wavelengths are given:

• 400 nm 46.8
• 630 nm 49.1°
• 670 nm 47,5°
• 780 nm 44,6°
• 795nm 45,7°
• 810 nm 46.8°
• 850 nm 49,9°
• 915 nm 43,3°
• 980 nm 47,3°
• 1010nm 49,3°
• 1060nm 47,9°
• 1300nm 40,5°
• 1350nm 42,4°
• 1600nm 46,1°