O'Dae Kwon

Angle-dependent multiple-wavelength radial emissions in a toroidal microcavity : (A Photonic Quantum Ring Laser)

We report for the first time angle-dependent multiple- wavelength emissions over 30 nm range from a toroidal cavity, which is a photonic quantum ring laser naturally formed in a VCSEL structure, with an ultralow threshold approaching the (mu) A-range consistent with Yarivs quantum wire view.

Spectrum of three-dimensional photonic quantum-ring microdisk cavities: comparison between theory and experiment

The spectrum of a three-dimensional Rayleigh-Fabry-Perot microdisk cavity of a photonic quantum-ring laser is analyzed for angle-dependent emission modes. It is shown that joint consideration of the Fabry-Perot resonance condition and the whispering-gallery mode boundary condition explains the emitting angles and spectral distribution of the cavity modes well.

Wet etching fabrication of photonic quantum ring laser

We present a wet etching process to fabricate good vertical mesa structures that result in high quality (Q) factors up to 2×104, important for smooth sidewall cavities such as the photonic quantum ring (PQR) laser. Q factor analyses also indicate that it can be improved much more once the internal scattering from the wafer materials is minimized. We use an etching solution of H3PO4:CH3OH:H2O2 with a volume ratio of 3:1:1, and a single-layer photoresist etch mask for etching GaAs∕AlGaAs structures of the PQR laser several micrometer deep. As the etching temperature is varied from 20to40°C, the etched surface roughness decreases from 4.690to0.703nm according to scanning electron microscope and atomic force microscopy studies. From the activation energy analysis for the above etching process and the temperature dependence, the etching process is shown to be reaction limited. The PQR lasers with an active diameter of 10μm, fabricated by the wet etching process, show the spectral linewidth of 0.04nm. Three-dim...

LaGuerre–Gaussian Emission Properties of Photonic Quantum Ring Hole-Type Lasers

We report on the observation of LaGuerre-Gaussian (LG) beam profiles of photonic quantum ring (PQR) hole-type lasers. Naturally formed LG beams are highly valuable for optical tweezering applications, like transporting or manipulating DNA molecules. Various devices with different injection currents and hole diameters have been analyzed.

Resonance spectrum of a three-dimensional photonic quantum ring laser with an equilateral triangle microcavity

We have fabricated three-dimensional (3D) photonic quantum ring lasers with an equilateral triangle microcavity. Their spectra were well explained by combining the off-normal resonance and hexagonally bounced in-plane whispering-gallery-mode condition. The angular distribution of the emission modes and their discrete wavelengths were shown to be in excellent agreement with a 3D Rayleigh Fabry-Perot model. We confirmed that the allowed modes in the equilateral triangle microcavity decrease by decreasing the length of equilateral triangle side, L, and the spectral mode spacing linearly increases with the mode index m and is inversely proportional to L2.

Investigation on photonic-corral-mode quantum ring lasers by laser scanning microscopy

Ultra low threshold microcavity lasers are ideal candidates for high-density optical interconnect light sources. Although they have been extensively studied for the last decade, muA-level electro-pumped quantum confined lasers are still under investigation. Photonic-corral-mode quantum ring (PQR) lasers with the linewidth narrower than 0.55 Aring generate micro-to-nano-ampere thresholds, and become ideal for CMOS-driven high-density emitter arrays for intra-chip optical interconnect as well as other applications such as displays. The PQR offers the following advantages for extremely high-density emitter source chip, over other semiconductor lasers presently available: a photonic quantum corral effect leads to naturally-born quantum wire behaviours for imminently recombinant carriers; the muA - nA threshold current capabilities mean kilo to mega PQR chip; radicT - dependent spectral red shifts are smaller at high operating temperatures, allowing uniform and reliable chip emission with minimal temperature sensitivities. By using laser beam induced current technique (LBIC) technique in laser scanning microscopy (LSM) we investigated the photocurrent confinement in the laser structure. The photocurrent map gives the possibility to analyze the laser structure uniformity.

Mega-pixel laser chips of photonic quantum ring holes for optical manipulation of biological cells

We report on a new, simple, effective and fast cell sorting method for massive micro-manipulation of biological cells or small particles in microfluidic channel involving a sorter-on-mega photonic quantum ring (PQR) hole laser chip scheme.

PQR laser can outdo LED

The PQR laser with ultra-low threshold current and sharp discrete multi-mode properties outdo conventional LEDs. We have fabricated 16times16 mesa type red PQR laser arrays at lambda = 610 nm and confirmed the superiority in luminous efficiency of PQR arrays to the conventional LEDs. We also present blue PQR laser arrays from GaN structures, which are very promising for display applications as well as low power high efficiency solid state lighting.

Spectral analysis of a three-dimensional photonic quantum ring laser with a square microcavity

Three-dimensional photonic quantum ring lasers with a square microcavity were fabricated and their spectra were explained by combining two conditions: the off-normal Fabry-Perot resonance and quadruple-bounced whispering-gallery mode. The angular distribution of the emission modes and their discrete wavelengths were in excellent agreement with a three-dimensional Rayleigh-Fabry-Perot model. The three-dimensional model also showed that the slope of the spectral mode spacing and the value of the angular mode spacing as a function of the length of a square side L are inversely proportional to L2 and L, respectively.

Photonic quantum corral, carrier ordering, and photonic quantum dot/ring device

Abstract This study aims at firstly introducing a theoretical background of photonic quantum ring naturally formed by photonic quantum corral effect in the 3D Rayleigh–Fabry–Perot micro-cavity. This unique phenomenon is visualized as polar angle-dependent multi-chromatic emission spectra corresponding to an each lightwave with different optical paths. Also, we fabricated an H-D structure for a single PQR, i.e. single mode within a luminescent wavelength region and ultra-low threshold 16-K PQR laser array for such as free space optical interconnections.