Short Pass Filter in Standard Detection Path
- 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
- 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.