Disclosed is a light emitting device having vertically stacked light emitting diodes. A channel encloses the dampening hinge member and provides a flow of air to the dampening hinge member. The invention further provides regulatory sequences and use thereof in various fields such as, but not limited to, protein production, diagnostics, transgenic plants and animals, and the therapeutic field. For example, the holographic element may additionally collimate ambient light or diffuse light reflected form the light modulators.