Daylight visibility of Laser Beam Daylight Visibility of
Daylight visibility of Laser Beam Daylight Visibility of a k. Hz - but µJ – Laser Beam Eastbourne, Kuratoriums - Sitzung Graz, 2003 -1125 October 2005
Hardware Setup Video Day/Night Frame Grabber Day/Night; 5 % of 532 nm Sensi. CAM ISIT-TV Old CCD Night only (10 Hz & k. Hz; bigger FOV) Filter 0. 3 nm 95% of 532 nm 50 cm Main C-SPAD Telescope Dichroic Mirror Kuratoriums - Sitzung Graz, 2003 -1125 Eastbourne, October 2005
Sensi. CAM - CCD § § Problem: Backscatter of Single Shot TOO WEAK (400 µJ) § NOT Visible with CCD. . . Solution: Integrate Backscatter of 1000 Shots. . . § But do NOT Integrate the noise between shots ! § => Increases Signal / Noise Ratio ! Laser Pulses 1000 Exposures 50 µs Exposure per Shot; Backscatter image only 1000 Shots integrated; needs 0. 5 s / image @ 2 k. Hz Kuratoriums - Sitzung Graz, 2003 -1125 Eastbourne, October 2005
CCD used in Graz Ø Ø Sensicam 360 KF; from PCO Imaging (www. pco. de) Camera type: Interface type: PCI-Board 525 KP (Koax Version Programming: via the C++ Package included with the CCD; Allows now for: Ø Continuous imaging of backscatter (no mirrors switched); Ø Uses only about 5% of the backscatter (leakage of dichroic mirror, which separates 532 from other wavelenghts); Ø Also used for rough visual adjustment of beam divergence. . . Ø Future Plans: Automatic Detection of Laser Beam Peak Ø Automatic Beam Centering with Remote Controlled Mirror (manually adjusted now) Kuratoriums - Sitzung Graz, 2003 -1125 Eastbourne, October 2005
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