Tuna are unique among teleost fishes in being thermoconserving. Vascular counter-current heat exchangers maintain body temperatures above ambient water temperature, thereby improving locomotor muscle efficiency, especially at burst speeds and when pursuing prey below the thermocline. Because tuna also occasionally swim rapidly in warm surface waters, it has… (More)
Recent experiments on similarly shaped polymer microcavity lasers show a dramatic difference in the far-field emission patterns. We show, for different deformations of the ellipse, quadrupole and hexadecapole, that the large differences in the far-field emission patterns are explained by the differing ray dynamics corresponding to each shape. Analyzing the… (More)
We study lasing emission from asymmetric resonant cavity GaN microlasers. By comparing far-field intensity patterns with images of the microlaser we find that the lasing modes are concentrated on three-bounce unstable periodic ray orbits; i.e., the modes are scarred. The high-intensity emission directions of these scarred modes are completely different from… (More)
'Mah-jong epilepsy' is a rare reflex epilepsy syndrome, manifesting as recurrent epileptic seizures triggered by either playing or just watching mah-jong. We present three patients with this condition and review all the reported cases. Mah-jong-induced seizures can be considered a subtype of cognition-induced epilepsy. Nonetheless, these patients have… (More)
When dye-doped ethanol droplets are irradiated with an intense pulsed laser beam, the resulting laser emission from individual droplets highlights the liquid-air interface. Photographs of the lasing droplets in the micrometer size range taken in a single 10-nanosecond laser pulse clearly show the dynamic changes in droplet size, shape, and orientation.
Asymmetric resonant cavities with highly noncircular but convex cross sections are predicted theoretically to have high-Q whispering gallery modes with highly anisotropic emission. We develop a ray dynamics model for the emission pattern and present numerical and experimental confirmation of the theory.
We report unidirectional emission from lasing in In 0.09 Ga 0.91 N/In 0.01 Ga 0.99 N multiple-quantum-well spiral micropillars. Our imaging technique shows that the maximum emission comes from the notch of the spiral microcavities at an angle about 40° from the normal of the notch. At room temperature, the spiral microcavity lases near 400 nm when optically… (More)
It is proposed that the spoiling of high Q whispering gallery modes in deformed dielectric spheres can be understood as a transition to chaotic ray dynamics which can no longer be confined by total internal reflection. This is a KAM/Lazutkin transition for light. The theory is applied to explain the lasing properties of droplets. The highest Q optical… (More)
We report on progress in developing optical microresonators and mi-crolasers based on deformations of dielectric spheres and cylinders. We review the different semiconductor and polymer dye microlasers which have been developed and demonstrated using this approach. All the lasers exhibit highly directional emission despite the presence of ray chaos in the… (More)
By combining detailed imaging measurements at different tilt angles with simulations of ray emission from prolate deformed lasing micro-droplets, we conclude that the probability density for the lasing modes in a three-dimensional dielectric microcavity must reside in the chaotic region of the ray phase space. In particular, maximum emission from such… (More)