I was informed this morning that the laser was off, as there was no infrared light showing up on the video cameras.  Went to the diode room and saw that the crystal chiller was indicating a flow sensor error.  The water level was about the same as it was previously, so there were no water leaks.

I turned the crystal chiller on from the PSL Computer, the flow rates indicated were normal.  Turned the laser back on, everything seems okay.  I do not know what triggered the flow sensor error in the first place.