Search for: All records

This study examines the lasing performance of optically pumped wurtzite‐phase InP nanowire (NW) photonic crystal surface‐emitting lasers (PCSELs) with the goal of optimizing the cavity design for low‐threshold lasing. By varying the photonic crystal lattice constant and NW diameter, this study systematically investigates the threshold power and the threshold gain. Using finite‐difference time‐domain simulations and gain spectra modeling, this study finds that the lowest pump threshold occurs when the cavity resonance energy is slightly above the spontaneous emission maximum energy due to high differential gain. Furthermore, PCSEL structures with an apothem‐to‐pitch ratio of ≈0.15 are advantageous because they provide increased confinement factors, resulting in the lowest lasing threshold and high laser output. This study paves the path toward low‐threshold NW PCSEL designs for photonic integrated circuits. 

We demonstrate unique reflective properties of light from bare and gold-coated InP nanowire (NW) photonic crystal arrays. The undoped wurtzite InP nanowire arrays are grown by selective area epitaxy and coated with a 12-nm thick Al₂O₃film to suppress atmospheric oxidation. A nominally 10-nm thick gold film is deposited around the NWs to investigate plasmonic effects. The reflectance spectra show pronounced Fabry-Perot oscillations, which are shifted for p- and s-polarized light due to a strong intrinsic birefringence in the NW arrays. Gold-coating of the NW array leads to a significant increase of the reflectance by a factor of two to three compared to the uncoated array, which is partially attributed to a plasmon resonance of the gold caps on top of the NWs and to a plasmonic antenna effect for p-polarized light. These interpretations are supported by finite-difference-time-domain simulations. Our experiments and simulations indicate that NW arrays can be used to design micrometer-sized polarizers, analyzers, and mirrors which are important optical elements in optoelectronic integrated circuits. 

Abstract This work investigates the polarization state of light diffracted from uncoated and gold‐coated InP nanowire photonic crystal arrays grown by selective area epitaxy. Experimental data and finite‐difference time‐domain simulations show that both the intensity and the ellipticity of the polarization state of the diffracted light beam can be controlled by the nanowire dimensions and gold coating, while the diffracted angle remains unchanged with respect to variations of these parameters. A nominally 10 nm‐thick gold film deposited around the nanowires enhances the diffraction intensity by plasmonic effects. These results demonstrate that the controlled conversion of incident linearly polarized light to circularly polarized or rotated linearly polarized diffracted light can find applications in photonic integrated circuits. The high sensitivity of the polarization state with respect to alterations of the nanowire dimension opens new prospects in the areas of semiconductor metrology and microchip inspection as well as for submicron particle detection. 

Abstract 2D photonic crystal (PhC) lasing from an InP nanowire array still attached to the InP substrate is demonstrated for the first time. The undoped wurtzite InP nanowire array is grown by selective area epitaxy and coated with a 10 nm thick Al₂O₃film to suppress atmospheric oxidation and band‐bending effects. The PhC array displays optically pumped lasing at room temperature at a pulsed threshold fluence of 14 µJ cm⁻². At liquid nitrogen temperature, the array shows lasing under continuous wave excitation at a threshold intensity of 500 W cm⁻². The output power of the single mode laser line reaches values of 470 µW. Rate equation calculations indicate a quality factor ofQ ≈ 1000. Investigations near threshold reveal that lasing starts from isolated islands within the pumped region before coherently merging into a single homogeneous area with increasing excitation power. This field emits a lasing mode with an average off‐normal angle of ≈6°. Single mode lasing with the nanoarray still attached to the InP substrate opens new design opportunities for electrically pumped PhC laser light sources.