Broadband Frequency-Tunable Whispering-Gallery-Mode Superradiant Light from Quantum Dots in Colloidal Solution

Figure 8

(a) Relationship between pump power and average line width of QD-3 embedded on SMA. (b), (c), and (d) are spectra obtained for corresponding pump energy; (A) and (B) were laser induced photoluminescence and had FWHM of 30 nm. Spectra (C) was obtained when the pump energy was between 2 and 4 mJ. Spectra (D) were also obtained when pump energy is at 2 to 4 mJ, but the WGM was produced due to high random feedback. Spectra (F) were obtained for pump energy more than 5 mJ up to 18 mJ.

(a)

(b)

(c)

(d)