Effect of a photonic band gap on the threshold and output power of solid-state lasers and light-emitting diodes

We present results for the operation of a three-level solid-state laser both with normal and with completely suppressed spontaneous emission between the lasing levels. The output power difference in these two cases drops as the pump rate is increased above threshold and is not greatly different at higher powers. The threshold pump power, although typically reduced by an order of magnitude, is not zero and our results thus throw further light on the concept of “thresholdless” lasing. The theory is also applicable to light-emitting diodes and amplifiers which function on the same principles as a laser.