Lasing characteristics of photonic crystal lasers studied by scanning near-field optical microscopy
Scanning near-field optical microscopy (SNOM) with high resolution is used to study filed distribution and lasing characteristics of photonic crystal laser. By power-dependent micro-PL, we study the optical properties of lasing process in the cavity. Power-dependent micro-PL results show that PL intensity will be increased, FWHM narrowed and resonance wavelength blue shifted with slowing down gradually when the excitation power is increased. The variation of PL intensity, FWHM, and wavelength is observed during the lasing process by experiment of SNOM which can obtain the full spectra in space. The distribution of electric field and lasing region affect the PL intensity of spatial distribution in photonic crystal cavity. Observing spatial distribution of variation of FWHM can determine the area of lasing. Besides, photonic crystal is excited by the power which is below threshold, free carrier effect is dominant and shifts the resonance peak to shorter wavelength in the defective center. The influence of free carrier plasma effect becomes secondary gradually when excitation power is above threshold and then local heating effect becomes dominant influence. The resonance peak in defective center is local heated and it is shifted to longer wavelength.
|Appears in Collections:||Thesis|
Files in This Item: