Zhi-Jian Wei

Punctuated island growth: An approach to examination and control of quantum dot density, size, and shape evolution

The later stages of the evolution of epitaxical island quantum dots are examined systematically for InAs depositions on GaAs(001) following the conventional continuous deposition mode and an approach introduced here called punctuated island growth (PIG). The comparative study provides clear structural and optical evidence for a change in InAs island shape at a self-limiting lateral size, first reached for depositions ∼2 ML. The PIG approach has also allowed realization of the narrowest reported inhomogeneous linewidth of 23 meV for low temperature photoluminescence from a single layer of binary InAs/GaAs quantum dots.

Operation of photonic crystal membrane lasers above room temperature

Operation of photonic crystal lasers for substrate temperatures as high as 50 °C is reported. The temperature dependence of the lasing wavelength and the threshold pump power is also investigated. The characteristic temperature To is 37.7 K.

Sapphire-bonded photonic Crystal microcavity lasers and their far-field radiation patterns

Room-temperature continuous-wave lasing was demonstrated in photonic crystal microcavities with diameters of approximately 3.2 /spl mu/m. Far-field radiation patterns of these lasers were experimentally measured and compared with numerical simulation predictions.

Room-temperature operation of VCSEL-pumped photonic crystal lasers

Room-temperature operation of two-dimensional photonic crystal lasers optically pumped by a vertical-cavity surface-emitting laser emitting at 860 nm is reported. The photonic crystal membrane is surrounded by air on both sides and consists of four compressively strained quantum wells as the active region. The incident threshold pump power of an approximately 2.6-/spl mu/m-diameter hexagonal defect cavity laser operating at 1.6 /spl mu/m is 2.4 mW.

Experimental characterization of the optical loss of sapphire-bonded photonic crystal laser cavities

Sapphire-bonded photonic crystal laser cavities with varying number of photonic crystal periods were studied in order to determine the optical loss in these cavities. The lasing threshold increases as the number of lattice periods decreases, and the quality factors of these cavities were calculated from the lasing threshold data. Continuous-wave operation was achieved for cavities with eight or more cladding periods

Linewidth and modulation response of two-dimensional microcavity photonic crystal lattice defect lasers

Linewidth and small-signal modulation response measurements are reported for room-temperature-operating microcavity two-dimensional photonic crystal lasers. The measured optical linewidth versus the output power was found to saturate at values on the order of 1 GHz. The modulation bandwidth for these low-power lasers was demonstrated to be on the order of 10 GHz

Room temperature operation of VCSEL-pumped photonic crystal lasers

Recently, photonic crystal defect lasers with different designs and cavity sizes have been realized. Here we present results on photonic crystal lasers optically pumped by a vertical cavity surface-emitting laser (VCSEL). This demonstration validates the low threshold potential of these laser elements and suggests a technique for their excitation.

Linewidth measurement of sapphire-bonded 2-D photonic crystal lasers

The linewidth of 2-D photonic crystal microcavity lasers was measured using the self delayed optical homodyne technique.

Sapphire-bonded photonic crystal lasers

Direct wafer bonding between InGaAsP/InP and sapphire is demonstrated. CW lasing is demonstrated in two-dimensional photonic crystal microcavities formed in this material.

Characterization of photonic crystal structures

The basics devices characteristics of photonic crystal lasers and passive components are introduced followed by a more detailed discussion of the experimental characterization of these devices.