Study on properties of microcavity resonance of AlGaInP based hexagonal photonic crystal

At present, the high power of the red semiconductor laser has been achieved. Improving the beam quality and reducing the divergence angle of the device have become urgent problems to be solved. The red semiconductor laser using photonic crystal as the waveguide has a confinement effect on the optical field, can restrain the high-order mode lasing and reduce the fundamental mode loss, and improve the performance of the cavity. In this paper, a cavity structure of AlGaInP-based photonic crystal with defect holes is proposed to achieve short-wavelength red resonance with high quality (Q) factor and small mode volume (V_m). The working mechanism of photonic crystal cavity with defect holes is studied by energy band analysis. Based on the principle of defect local state and edge of photonic crystal band, in-plane feedback, high Q-factor resonance and out-of-plane vertical emission of photons are realized. The resonant properties of the defect region and the non-defect region are studied using finite difference time domain (FDTD) method. The dependence of the Q-factor, cavity loss, resonant frequency on the parameters of the cavity is discussed. The results demonstrate that the in-plane loss can be effectively reduced by the photonic crystal defect holes, and the resonant wavelength is 640.569 nm. Finally, the Q-factor reaches over 10⁷ and the mode volume is only 0.61(λ/n)³.