Michael Hooker Microscopy Facility (MHMF.ORG)

Short Pass Filter in Standard Detection Path Before PMTs

Description:

• A BA685 short pass filter is present in the detection optical path before the confocal pinhole and PMTs, and cuts light with wavelengths longer than 685 nm.
• 
• Transmission of hlogen desk lamp with the BA685 filter in (on top) and without the BA685 filter (bottom).
• Spectral scan acquired with a 20/80 beam slitter and 5 nm acquisition bins.  10x dry objective, lamp placed over condenser.  No lasers were turned on.

Considerations for imaging:

• This filter cuts of light with wavelengths longer than 685 nm.
  • The filter roll off is steep and it is suspected that the cut off band to pass band ratio is in the order of more than 4 OD units.
  • This filter will significantly reduce the signal from CY5, Draq-5 and other far red dyes.
  • Emission for dyes with emissions similar to CY5.5, CY7, FM 4-64 will be cut off almost totally
• This filter can be removed by facility personnel
• Removing the filter may affect alignment to the single detection path to the PMTs relative to the single photon laser excitation path.
• Miss alignment may reduce resolution, detection efficiency and localization of the fluorescence image with the transmitted light image in 3-D space

Overview:

• It is believed that the function of this this filter is to cut off reflections from the Ti:sapphire laser (690 to 180 nm) when the mutiphoton imaging is being carried out.

		Copyright 2001-2015  Dr. M. Chua, School of Medicine, University of North Carolina, Chapel Hill, NC 27599
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