By the two-dimensional triangular holey structure, a high-power stable single-mode operation was demonstrated in oxide confined 850 nm vertical-cavity surface-emitting lasers. For two types of hole alignments, the lasing operation was observed with different near field patterns, i.e., a single spot pattern and a floral pattern. The former showed an output power of 2 mW with a high side-mode suppression ratio (SMSR) of 45-50 dB, which is explained by the selective loss mechanism. The latter showed a high power of 7 mW with a SMSR of 40 dB. The observed lasing spectrum and far field pattern indicate that it is a deformed fundamental mode whose bright spots extending over the device are in-phase oscillating. This device structure will be effective for the enhancement of single-mode power in devices with any material system. (C) 2004 American Institute of Physics.