Figure 1
(a) Schematic of the InGaN VCSEL structure. (b) Experimental apparatus. Osc.: Ti:sapphire oscillator; Reg.: regenerative amplifier; M: mirror; L: lens; BS: beam splitter; BBO: β-BaB2O4 crystal; SF: sum-frequency; BPF: band-pass filter, SPF: short-pass filter; P: polarizer; PMT: photomultiplier tube; PC: personal computer. (c) Pulse-lasing spectrum of the gain-switched InGaN VCSEL at room temperature. The inset shows the enlarged lasing spectra with various pump powers above the threshold, where the arrow indicates the increase in pump power. Note the spectral broadening toward short wavelengths as the pump power increases. (d) Plot of input vs. output of the InGaN VCSEL. (e) Enlarged spectrum of the InGaN VCSEL with pump power below the threshold. Solid curves are Gaussian fits of the modes. FWHM: full width at half maximum. FSR: free space range.
