William Angerer - Department of Physics and Astronomy - University ...

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operation while wearing a pair of alignment goggles. Note that a beam is reflected
off of the Brewster window. It is necessary to identify and avoid this beam prior
to observing the Brewster window. Once the contaminant is identified. the window
should be cleaned with HPLC grade methanol. I have found that cleaning a contaminated
Brewster window with methanol occasionally does not remove the contaminant.
The contaminant may be removed by etching the window with Ammonium Bifloride
(ABF). The .-\BF cleaning procedure may be obtained from Coherent Laser Group .
.-\nother potential problem is the spatial mode of the pump beam, which may
also be distorted by dust on the pump beam optics. These optics are extremely
susceptible to picking up dust, and must be cleaned frequently (once a week). An
additional technique to optimize the performance of the Ti:AI 2 0 3 laser is to "walk"
the Ti:.-\h03 beam to the center of every mirror in the laser cavity. This procedure.
which is outlined in the manual. ma.ximizes the overlap of the Ti:AI 2 0 3 beam with
the pump beam, and hence maximizes the Ti:Ah03 power. In my experience. this
procedure often produces an increase in power necessary for modelocked operation.
It is equally important to center the Argon pump laser on the pump optics while
simultaneously centering the pump beam on the Ti:AI 2 0 3 crystal. The procedure for
centering the beam on the crystal is not in the laser manual, but I have observed
the Coherent field service engineers employ this method to increase the power of
the Ti:Ah03 laser. The reader is referred to the laser manual to identify the optics
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