Laser mode feeding by shaking quantum dots in a planar microcavity

Semiconductor light emission can be changed considerably in an optical resonator(1). Prerequisite is that the electronic transitions involved in light generation are in resonance with a cavity mode. Although resonance can be arranged through dedicated fabrication, there are cases where this is virtually impossible. As an example, we study a planar microcavity containing an inhomogeneous quantum dot ensemble with a spectral broadening much larger than the optical mode width, so that resonance is achieved for a tiny dot fraction only. Still, the laser threshold can be crossed at moderate optical pumping. We demonstrate that strain pulses generated by ultrafast acoustics techniques can be used to modulate the transition energies so that resonance with the optical mode is dynamically induced for a much larger dot fraction. As a result, the emission output can be enhanced by more than two orders of magnitude, which is potentially useful for modulating light sources.