  We experimentally demonstrated high quality factors (Q-factors) of
nanocavities in three-dimensional photonic crystals by increasing the in-plane
area of the structure. Entire structures made of GaAs were fabricated by a
micro-manipulation technique, and the nanocavities contained InAs
self-assembled quantum dots that emitted near-infrared light. The obtained
Q-factor was improved to 93,000, which is 2.4-times larger than that in a
previous report of a three-dimensional photonic crystal nanocavity. Due to this
large Q-factor, we successfully observed a lasing oscillation from this cavity
mode.
