DazScope
manual Chapter 2 : Installation
3. Set the width control to 2 or 3 times4the FWHM spectral width of the input or amplified
pulses plus the value of the potential redshift5.
4. Set the hole depth control to 0.
Phase parameters (green area)
1. Select the dials item in the listbox located just below the green Phase label.
2. If the central wavelength of the amplified pulse (λ0) is close to the value of the position
control, check the Auto checkbox located at the bottom of the phase control (green panel)
area. If this is not the case, uncheck this checkbox and enter manually the value of λ0in the
Central wavelength control. This will ensure that the spectral phase coefficients will refer
to the right central wavelength6.
3. Set the delay dial to a value corresponding to half of the maximum crystal delay (for example,
1700fs for 25mm WB-800), verify that the mean position on the time display is in the middle
of the window.
4. Press the SelfC button which is located on the left of the Phase listbox. This will automat-
ically set the phase coefficients to compensate for the dispersion of the Dazzler crystal.
5. Check that the spectrum graph does not show separate red and black curves. If so, check
maximum delay and reduce second order parameter (order 2) if necessary.
Trigger parameters
Since all laser systems have different synchronization managements, it is difficult to specify a
universal process to set up the trigger parameters. Here is however, the most common way to
proceed:
1. Click in the Setup menu, select Trig and mode : this will open the corresponding panel.
2. In the Trigger mode listbox select External Source.
3. Check that the displayed repetition rate is correctly measured by the generator. If the
displayed repetition rate is wrong, check the trigger signal (see subsection 2.2.2).
4. In the Delay Mode listbox select Programmable Trigger Delay. This will activate the delay
generator module of the RF generator.
5. Check that the Trigger on previous checkbox is not checked.
6. In the Trigger to Laser control, enter the delay between the trigger signal (TTL rising
edge) and the laser pulse7.
4This is a rule of the thumb.
5E.g.: for an amplified spectral width of 30nm with a red-shift of 10nm, the width control must be set to 100nm
6The phase coefficients (second order, third order etc) refer to a Taylor expansion of the spectral phase around
λ0. If ”auto = 1”, λ0is assumed to be equal to the ”position” amplitude control
7with a microsecond accuracy at least
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