Steady-state ab initio laser theory : generalizations and analytic results

• Main Authors: Ge, Li, Chong, Yidong, Stone, A. Douglas
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2013
• Subjects: DRNTU::Science::Physics
• Online Access: https://hdl.handle.net/10356/101160; http://hdl.handle.net/10220/18340
• Institution: Nanyang Technological University

We improve the steady-state ab initio laser theory (SALT) of Türeci et al. by expressing its fundamental self-consistent equation in a basis set of threshold constant flux states that contains the exact threshold lasing mode. For cavities with nonuniform index and/or nonuniform gain, the new basis set allows the steady-state lasing properties to be computed with much greater efficiency. This formulation of the SALT can be solved in the single-pole approximation, which gives the intensities and thresholds, including the effects of nonlinear hole-burning interactions to all orders, with negligible computational effort. The approximation yields a number of analytic predictions, including a “gain-clamping” transition at which strong modal interactions suppress all higher modes. We show that the single-pole approximation agrees well with exact SALT calculations, particularly for high-Q cavities. Within this range of validity, it provides an extraordinarily efficient technique for modeling realistic and complex lasers.