The increasing complexity of cold atom experiments puts ever higher demands on the stability and reliability of its components. We present a laser system for atom cooling experiments, which is extremely reliable yet simple to construct and low-cost, thus forming an ideal basis for ultracold atom experiments such as Bose-Einstein condensation and degenerate Fermi gases. The extended cavity (master) diode and slave lasers remain locked over a period of months with a drift in absolute frequency well below 1MHz with a line-width of less than 300kHz. We generate the repumper light by modulating the current of an injection locked slave laser at a frequency of 6.6GHz. The construction of the laser is simple and largely based on off-the-shelf electronic and optomechanical components.
The basic idea of this laser system is to keep the individual elements modular, so that a fault in one part of the system can be repaired by only changing the sub-system with zero changes elsewhere. Each parts in the graph on the right thus represents a separate bread-board.
The article also describes a very simple diode laser with extraordinary long term stability (depicted here on the right). This master-laser uses simply to machine parts and a commercial mirror mount for holding the grating. The diode holder and mirror mount are screwed onto an aluminium base plate, which is glued onto a Peltier element, which in turn is glued onto a base. The whole assembly is then surrounded by thick-walled aluminium box, which has been lined with standard isolation foam.
Another key element are the distribution and AOM breadboards. They consist of standard 40mm kitchen-top granite plates cut to 300x600mm. The optical mounts are 1” aluminium posts which are glued onto the base plate using cyanoacrylate adhesive (Loctite 408). The beam hight is 50mm.
– Layout of the AOM board (including alignment procedure) (link)
– Layout of the distribution board (including alignment procedure) (link)
– Electronics Diagramms (link)
– Technical drawings of the master laser (link)
– Technical drawings of the slave laser (link)