Coherently induced one-dimensional photonic band gap

We show theoretially that a one-dimensional photonic band gap can be generated by coherent optical processes in n-doped semiconductor quantum wells using intersubband transitions. This is illustrated in a waveguide structure where an optical field that is nearly resonant with such transitions induces resonance enhancement of the refractive index with vanishing absorption. For a particular InGaAs/AlGaAs quantum well structure we show that a 3.2 $\mu \mathrm{m}$ beam with intensity $\sim 1.9{\mathrm{M}\mathrm{W}/\mathrm{c}\mathrm{m}}^2$ can generate an active photonic band gap centered at $\sim 4.55$ $\mu \mathrm{m}$ with more than 10 nm width and no loss.