LabAdviser/314/Microscopy 314-307/Technique/Holo/Off-axis ATEM: Difference between revisions
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# Correct for objective lens astigmatism. For every magnification change you should recheck objective lens astigmatism and the focus (with the focus knob). You do the rotation centering at the beginning and not when you play with the magnification-control. <br/><br/> | # Correct for objective lens astigmatism. For every magnification change you should recheck objective lens astigmatism and the focus (with the focus knob). You do the rotation centering at the beginning and not when you play with the magnification-control. <br/><br/> | ||
# Acquire a reference hologram with acquisition time of 10 s and if it is noisy reacquire the hologram with 10 s or 5 s. Then draw a spectrum line across a few fringes and see how many pixels are there per fringe. We should keep 4 pixels per fringe. To increase the number of fringes per unit are, increase the biprism voltage. A biprism voltage of 120-130V is recommended. | # Acquire a reference hologram with acquisition time of 10 s and if it is noisy reacquire the hologram with 10 s or 5 s. Then draw a spectrum line across a few fringes and see how many pixels are there per fringe. We should keep 4 pixels per fringe. To increase the number of fringes per unit are, increase the biprism voltage. A biprism voltage of 120-130V is recommended. | ||
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== Finishing-up the holography part of the measurement == | == Finishing-up the holography part of the measurement == | ||