30
SolsTiS User Manual v10.0
2.
As the required wavelength is approached, it may be helpful to change the
BRF speed progressively from MEDIUM to SLOW to STEP to avoid
overshoot.
Note!
When set to ‘STEP’, tap the mouse to tune the
BRF in single, high precision motor increments.
3.
When tuning (or frequency scanning) the laser, expect a slight delay and
hysteresis when making wavelength (frequency) adjustments via the UI.
Awareness of this characteristic will help avoid adjustment overshoot.
4.
If the BRF jumps to the next order (signified by a large jump in output
wavelength), recover this by reversing the BRF direction, accounting for
hysteresis.
5.
After large wavelength changes, SolsTiS’ intracavity beam path may
change slightly due to the dispersive nature of some of the optical
components in the cavity, and it may then be possible to increase output
power slightly by re-
optimising the POM ‘X’ alignment (≤
1/4 turn, as
described above).
6.
DIAGNOSTIC NOTE - if the BRF is inadvertently tuned to the next order,
or SolsTiS is operating on more than one longitudinal mode, a useful
indication of this is that the WSD readout will become nonsensical and
may suddenly jump wavelength (because the WSD is designed to read a
single frequency impinging on the WSD detector.)
Fine Wavelength Tuning
– Adjusting the Intracavity Etalon
(SolsTiS-LX, -PX, -PSX, -SRX)
Once the BRF Tune control has been used to tune SolsTiS’ wavelength to
within one etalon FSR of the user’s target wavelength, the user can then
move to the
Etalon Tune
adjustment. This control allows the user to fine tune
the set wavelength through a range of more than one étalon FSR (~0.15-
0.7nm), depending on the model purchased.
Note!
Use of a high precision wavemeter is
recommended to allow the user to observe the sub-
0.1nm wavelength changes that can be made with
the
Etalon Tune
control.
Note!
Before starting to make any adjustments to
SolsTiS’ output wavelength with the
Etalon Tune
control, it is recommended that the user first sets the
Etalon Tune
control to ~50% of its full range. This
ensures fine-tuning is not started near to either end of
an étalon FSR and hence minimizes the likelihood of
a wavelength jump to a neighbouring etalon
transmission peak during fine tuning. Similarly, it is
recommended that the required wavelength is also
set as closely as possible to the centre of the étalon
tuning range. This may require some iterative adjust
of the
BRF Tune
(a few single step clicks) and
Etalon
Tune
controls.
Note!
Unlike the
BRF Tune
control, the
Etalon Tune
control includes both single step (tap) and continuous
(hold) tuning functions on the same button.
1.
Before starting to make any adjustments to SolsTiS’ output
wavelength with
Etalon Tune
control, it is recommended that
the user first sets the
Etalon Tune
control to ~50% of its full
range so that fine tuning is not started near to either end of an
étalon FSR. This minimizes the likelihood of a jump to a
neighbouring etalon transmission peak during a fine-tuning
adjustment. (A jump to a neighbouring étalon mode will
manifest itself as a wavelength discontinuity or jump