Reduction of Lasing Threshold of GaN-Based Vertical-Cavity Surface-Emitting Lasers by Using Short Cavity Lengths

Green Vertical-Cavity Surface-Emitting Lasers Based on InGaN Quantum Dots and Short Cavity

“…The related physical mechanism can be attributed to the enhancement of the spontaneous emission coupling factor and the decrease of internal absorption loss. The spontaneous emission coupling factor can be significantly enhanced by 7.7 times when the cavity length was thinned from 18 to 6 λ in our previous work [ 56 ]. The spontaneous emission coupling factor ( β ) can be defined as the fraction of spontaneous emission coupled into a cavity mode with respect to the spontaneous emission into all modes [ 57 ], and depends on the Purcell factor of the cavity [ 56 ]: where Purcell factor F p relates to the cavity length [ 56 , 58 ]: where R , L c , and α i represent the reflectivity of top/bottom DBR (> 99.5%), cavity length, and absorption of VCSEL, respectively.…”

“…Meanwhile, a short cavity can also enhance the gain coefficient factor (κ). The factor (κ) can be expressed as follow [ 56 ]: where γ is the FWHM of the spontaneous emission without cavity, n is the refractive index of the resonant cavity, and Δυ c is the frequency spacing between longitudinal modes. Consequently, the gain coefficient factor (κ) can be derived as: …”

Design and simulation of vertical cavity surface emitting laser based on all-inorganic perovskite

“…Despite the fact that perovskites green light is more stable, it still needs to be upgraded in terms of performance. A variety of resonators, such as Fabry-Perot (FP) cavity, whispering gallery mode (WGM), distributed feedback (DFB) gratings, Distributed Bragg microcavities, have been demonstrated to achieve laser emission in combination with perovskite through limited light field enhanced coupling [10][11][12][13] . However, they also have flaws.…”

A simple and precise method for the threshold current determination in vertical-cavity surface-emitting lasers

“…Although the spontaneous emission in VCSELs is still the subject of active debate and research [11,12] and the clamping phenomenon is often used in VCSEL modelling [13], no measurement results of the spontaneous emission over the threshold in these lasers have been published to date. In this paper, we present the first experimental study of the clamping phenomenon in VCSELs and we propose a practical and fast method to determine the threshold current based on this phenomenon.…”