Direct bandwidth and polarization control of an XeF unstableresonator laser

Several approaches to directly controlling the bandwidth and polarization of an unstable resonator without the use of an injection source are discussed. The techniques are based on the control of oscillations within (and around) the resonator core through the use of small, subaperture optical elements (e.g. etalons, Brewster-angle plates, Glan-air prisms) mounted at select locations within the system. The experiments were performed on a 4-J, e-beam pumped, XeF ( B→X) laser operating at ambient temperature, with output predominantly at 353.2 nm. A spectral linewidth of less than 12 GHz (0.05 Å) and nearly perfect linear polarization were simultaneously achieved at high laser efficiency. Oscillation on a single, dominant transverse mode has been demonstrated. The increased cost and complexity of injection-controlled systems are avoided through the use of these direct, core-control approaches