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(a) Fitting the PL spectrum of the circular microdisk array at 800 mW with eleven Loren peaks. (Inset: the SEM image of the circular microdisk array); (b) the PL spectra of the unpattern film and the circular microdisk array with a size similar to the hexagonal microdisks at 16 K and excitation power of 800 mW. The power-dependent enhancement factor (EF) of (c) the hexagon
Source publication
The coupling between the quantum dots (QDs) and silicon-based microdisk resonator facilitates enhancing the light–matter interaction for the novel silicon-based light source. However, the typical circular microdisks embedded with Ge QDs still have several issues, such as wide spectral bandwidth, difficult mode selection, and low waveguide coupling...
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... the m ture gas of SF6 and C4F8 is used for etching at low power for the fabrication of the circu microdisks. Figure 5a shows the PL spectra of the circular microdisk and their spectru fitting with eleven Lorentz peaks. The integrated PL intensity among 1350-1650 nm of t circular microdisk array is ~1.2 times stronger than that of the unpatterned film. ...
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... the mixture gas of SF 6 and C 4 F 8 is used for etching at low power for the fabrication of the circular microdisks. Figure 5a shows the PL spectra of the circular microdisk and their spectrum fitting with eleven Lorentz peaks. The integrated PL intensity among 1350-1650 nm of the circular microdisk array is ~1.2 times stronger than that of the unpatterned film. ...
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... defined in Equation (3) is based on a direct comparison of experimental data, providing a direct description of the PL enhancement of Ge QDs luminescence in GeSi materials by microdisks structure. The EFs of the hexagonal microdisk and the circular microdisk array as a function of wavelength are shown in Figure 5c,d, respectively. Four EF peaks correspond to the wavelengths of peaks H2, H4, H6, and H7 are shown in Figure 4c with a maximum EF value is 20.4 for peak H6. ...
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... EF peaks correspond to the wavelengths of peaks H2, H4, H6, and H7 are shown in Figure 4c with a maximum EF value is 20.4 for peak H6. Meanwhile, the circular microdisk also exhibits peaks C6, C8, and C11 with EF values of 14.9 and 14.0 for peaks C8 and C11, respectively, as shown in Figure 5a,b. These EF values are significantly larger than 1 (Figure 5d), which is attributable to the Purcell effect of the cavity mode. ...
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... the circular microdisk also exhibits peaks C6, C8, and C11 with EF values of 14.9 and 14.0 for peaks C8 and C11, respectively, as shown in Figure 5a,b. These EF values are significantly larger than 1 (Figure 5d), which is attributable to the Purcell effect of the cavity mode. ...
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... further elucidate the experimental results, we conducted simulations and analyses of the optical fields corresponding to the modes of the EF peaks depicted in Figure 5c,d. Figure 6b exhibits the optical field distribution of the modes in the hexagonal and circular microdisks, including TE 6,1 (H4), TE 5,1 (H6), and TE 4,1 (H7) modes for the hexagonal microdisk and TE 7,1 (C6), TE 6,1 (C8), and TE 5,1 (C11) modes for the circular microdisk. ...
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... the perspective of light-matter interaction, we believe that a large value of η corresponds to a significant enhancement effect for the PL intensity of QDs in microdisks. As seen in Figure 6d, the TE 5,1 mode exhibits the highest value of η, which could be the primary reason for the maximum EF value of 20.4 observed for the H6 mode in Figure 5c. Combined with the previous discussion, it can reasonably explain the unique enhancements of the hexagonal microdisks for H6 mode compared to the circular microdisks with comparable sizes. ...
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... EF peaks correspond to the wavelengths of peaks H2, H4, H6, an H7 are shown in Figure 4c with a maximum EF value is 20.4 for peak H6. Meanwhile, th circular microdisk also exhibits peaks C6, C8, and C11 with EF values of 14.9 and 14.0 f peaks C8 and C11, respectively, as shown in Figure 5a,b. These EF values are significant larger than 1 (Figure 5d), which is attributable to the Purcell effect of the cavity mode. ...
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... th circular microdisk also exhibits peaks C6, C8, and C11 with EF values of 14.9 and 14.0 f peaks C8 and C11, respectively, as shown in Figure 5a,b. These EF values are significant larger than 1 (Figure 5d), which is attributable to the Purcell effect of the cavity mode. Th EF values of the circular microdisks (C6, C8) are close to previous results of the GeSi ci cular microdisks [15]. ...
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... this case, the hexagonal microdisk seems to have an advantage over the circular microdisk. To further elucidate the experimental results, we conducted simulations and analyses of the optical fields corresponding to the modes of the EF peaks depicted in Figure 5c,d. Figure 6b exhibits the optical field distribution of the modes in the hexagonal and circular microdisks, including TE6,1 (H4), TE5,1 (H6), and TE4,1 (H7) modes for the hexagonal microdisk and TE7,1 (C6), TE6,1 (C8), and TE5,1 (C11) modes for the circular microdisk. ...
Citations
... µm, which makes them promising for the creation of light sources for silicon photonics. The best results in QD emission enhancement were achieved by creating structures supporting high quality states [28][29][30][31][32][33][34][35][36]. The high quality factor is an inherent property of a special type of states, bound states in continuum (BIC) [37]. ...
In this paper, we study the effects of GeSi quantum dot emission coupling with the collective modes in the linear chains of Si disk resonators positioned on an SiO2 layer. The emission spectra as a function of the chain period and disk radius were investigated using micro-photoluminescence (micro-PL) spectroscopy. At optimal parameters of the disk chains, two narrow PL peaks, with quality factors of around 190 and 340, were observed in the range of the quantum dot emission. A numerical analysis of the mode composition allowed us to associate the observed peaks with two collective modes with different electric field polarization relative to the chain line. The theoretical study demonstrates the change of the far-field radiation pattern with increasing length of the disk chain. The intensive out-of-plane emission was explained by the appearance of the dipole mode contribution. The obtained results can be used for the development of Si-based near-infrared light sources.
The mechanisms underlying the stability of the intensity imbalance between the left‐ and right‐circulating lasing modes in a GaN hexagonal microdisk resonator are investigated. Finite‐difference time‐domain simulations reveal that the imbalance is determined by the position of the point light source (seed light for lasing) inside the resonator. The coupling mechanism between the resonance modes and light from the source is clarified using numerical calculations. In addition, it is confirmed that light is highly coupled with one of the circulation modes when the source is placed off the bilateral symmetry axis of the mode near the side of the resonator, without any influence of the polarization of the source. The results indicate that the imbalance of the lasing modes observed in the experiments is determined by the position of the seed light near the side of the resonator, which must be spontaneous emission from impurities or defects, such as donor–acceptor pairs, donor‐bounded excitons, basal plane stacking faults, or the transition of free electrons in the conduction band to acceptor levels et al.
