Figure 2 The laser mount and guidance system, with the laser beam path added in red (top) together with a close up of the goniometer, with the laser beam approaching the crystal from below (bottom). A 633  nm HeNe laser is shown, but 532  nm CW-Nd:YAG and 830  nm diode lasers have also been used. For these lasers the typical power at the sample is 2  mW, which should lead to a temperature increase at the sample of less than 1  K, indicating that the effects seen when using this device are photophysical rather than photothermal.

© International Union of Crystallography 2004