Laser Boosts Engine Efficiency?

There are many engineers out there tinkering to improve the performance of the automobile engine. Marlan O. Scully of Texas A&M University in College Station has taken it a step further, with the addition of a "quantum afterburner" to the Otto engine.

Scully, reporting in the Feb. 4 issue of Physical Review Letters, has brought quantum physics to bear on the ideal Otto cycle, which describes the four-stroke internal combustion engine. He suggests that using a maser to create a thermal population inversion in the hot waste gas that remains after combustion can squeeze out a little more energy. In the hypothetical system, the excited gas then passes into a laser cavity, where its energy can be extracted as photons.