InGaAlP quantum well microcavities of circular or deformed disks and disks with microstructures

Optical microdisk is based on circularly symmetric micro-resonator and featured of the `whispering-gallery' modes with high quality of factor Q. However, the non-preferred directional emission and lack of high output from the disk are its drawbacks for application. Recently, a remarkable advance in the novel deformed microdisk laser at middle-infrared wavelength is highly attractive. In this report, as a preliminary try for microdisk at visible range, the InGaAlP quantum well (QW) circular cylindrical and deformed microdisks with radii about 2.5 to 10 ??m emitting at wavelength of 0.62-0.67 ??m were prepared by electron beam lithography and wet etching processing etc. The optical emission properties of these microdisks are studied by employing the scanning electron microscopy, atomic force microscopy, fluorescence image microscopy and scanning near-field optical microscopy etc. The preferential emission in these deformed microdisks was visually observed. When the cross section of microdisk was gradually deformed from circle, the change of fluorescence image from uniform ring towards 2 or 4 favorable emission along the circumference of microdisks was confirmed. The deformation could be caused by either the shape or etching profile of the disk waveguide. In addition, the microdisks patterned with some microstructures were proposed.EI