Fig. 4. Characterization of the output of the BRW device.

a, Left, the output of the electrically excited BRW device was characterized using a standard laser-lab power meter. The measured average power (P_av) was converted into the instantaneous output power (P_out) using P_out = (T/τ_p)P_av. For τ_p = 1 μs and T = 1 ms used in our experiments, P_out = 1,000P_av. Right, photograph of the device operating at j = 170 A cm⁻² under ambient conditions in room light clearly shows edge emission that appears very bright despite the small on-time fraction (τ_p/T = 0.001) and the small size of the emitting spot (the nominal area is about 9 μm²). Scale bar, 10 mm. b, The dashed blue line shows the j-dependent instantaneous output power. At the maximal current density (j = 1,933 A cm⁻²), P_out reaches 170 μW. On the basis of the measured output power, we determine the EQE (red circles), which is compared with that of the reference device (black triangles). Owing to the efficient ASE, which leads to the increased QD emission rate and enhanced power extraction from the inverted QD medium, the EQE droop is much less pronounced in the BRW device. In particular, j_½ is about four times higher than that for the reference device (1,933 versus 500 A cm⁻²).