With this simplified version of the Channels tool, you control and adjust the laser and the detector in the Topography Measurement wizard. The following parameters are available:

Parameter

Description

405 nm

Here you can set the required attenuation (in %) of the laser using the slider, the arrows, or typing in the input field.

If different laser wavelengths are required for the topography acquisition, a z-stack needs to be acquired using the Acquisition tab. The acquired and stored z-stack can then be loaded in the topography wizard to calculate height map and EDF image in a second step.

Pinhole

Adjusts the diameter of the pinhole.

The diameter is specified in micrometer. The text below translates this diameter to Airy Units (AU) and section thickness.

For confocal topography measurements a pinhole size of 1 AU is recommended. Smaller pinhole diameters can increase contrast and resolution. Larger diameters increase the depth of field, reduce the number of images per z stack, and consequently shorten the measurement time at the expense of resolution.

-

1 AU

Sets the pinhole diameter to the recommended value of 1 AU (Airy Unit).

-

Max
(Default)

Opens the pinhole to its maximum diameter.

This is also the default setting for the pinhole. This allows you to easily focus on the surface just like with a widefield microscope. Of course, focusing via the eyepieces is also possible.

Master Gain

Here you can control the voltage of the PMTs. Higher voltage increases the gain of the PMT. The image becomes brighter and you may be able to reduce the laser power. At higher voltage, the noise level in the image increases.

The optimum between gain and noise depends on your experimental requirements and on your sample. The maximum available voltage for multialkali PMTs is 900V.

Digital Offset

Here you can perform adjustments on the background of the image.

Digital Gain

Here you can digitally amplify the laser signal.