The quantum Otto mobile and its application to directed energy

We show that it is possible to improve the efficiency of a laser system by adding a classical heat engine cycle to the laser gas that can remove both thermal and vibrational energy from the gas. A rapid pulsed CO2 laser/gas expansion cycle engine and a continuous CO2 laser, Stirling or Brayton cycle engine are analyzed. We derive a theoretical total energy recovery efficiency for a CO2 laser combined with a classical heat engine of 89%. Then, several distinctly different functional laser-coupled heat engine designs will be evaluated to determine the viability of these concepts in practice. Ultimate practical device efficiencies are projected to reach 75% efficiency.