Although lasing has been demonstrated in two-dimensional (2D) photonic-crystal nanocavities, researchers at the University of Tokyo (Tokyo, Japan) have for the first time demonstrated lasing in three-dimensional (3D) photonic-crystal nanocavities. The breakthrough is the first step toward realizing 3D integrated circuits and offers a new means to study light-matter interactions in 3D cavities.
The researchers overcame previous hurdles in building a high-Q, 3D cavity with a complete photonic bandgap by fabricating a 25-layer woodpile structure that includes gallium-arsenide-based 2D layers and an active layer composed of three layers of indium arsenide quantum dots, each with a dot density of approximately 4 × 1010 cm-2. This active layer creates a 1.15 × 1.15 μm embedded defect in the 3D structure that—together with an optimized number of 12 upper gallium arsenide layers to maximize Q to a value of 38,500—confines the cavity modes in a complete photonic bandgap between 1085 and 1335 nm. When pumped by 8 ns pulses with 150 mW peak pulse power at a 25 kHz repetition rate from a 905 nm laser, the 3D photonic-crystal nanocavity lased at approximately 1197 nm. Contact Yasuhiko Arakawa at [email protected].
