Calculation Of Achievable Pump Power And Gain In Al/Mg Resonantly Photopumped Laser

In 1984 Krishnan and Trebes discovered a sequence of Be-like ions ranging from C III to Mg IX which could be resonantly photopumped by closely matched lines from various other ions. If the pumped ions can be excited to the Be-like ground state, pumping of the 2s^{2 1}s - 2s4p¹P transitions with sufficient power would lead to gain in transitions ranging from 2163 Å to 230 Å. Indeed, the 2163 Å laser has already been demonstrated. The present calculations concentrate on the high Z end of this sequence, where an Al XI - Mg IX resonance could lead to gain near 230 Å. We assume that the aluminum plasma is produced in a megampere-class or larger Z pinch, and that the magnesium lasant is a separate plasma with properties distinct from those of the aluminum. Using detailed atomic physics models and assuming collisional-radiative equilibrium we address the following issues: 1) the line profile and monchromatic pump power output achievable from the Al pinch, 2) the Mg plasma conditions which are most favorable for gain, 3) the magnitude of the gain and the most attractive laser lines in Mg IX, and, 4) the advantages and disadvantages of this system relative to the well-known Na/Ne photoresonant laser.