Laser emission from photonic dots

Abstract

Laser emission was observed in photonic semiconductor dots with a discretized optical mode spectrum. The photonic dots with lateral sizes between 1 and 5 μm provide a three-dimensional optical confinement by using in the vertical direction AlAs/GaAs Bragg mirrors and in the lateral directions the refractive index discontinuity at the etched surfaces. In the optically pumped structures, the laser emission takes place on the fundamental mode of the microcavities. External threshold excitation densities of 200 W/cm2, which correspond to a very low internal optical excitation power of 0.15 μW per microcavity post, were measured for microcavity structures with a lateral size of 2.7 μm.

Angle dependence of the spontaneous emission from confined optical modes in photonic dots

“…Details of the fabrication process have been given elsewhere. 20 The cavity was etched through the top reflector and the GaAs layer down to the top of the bottom reflector. The lateral sizes of the dots were determined from scanning electron microscopy and ranged from 6 m down to 2.7 m.…”

Optical Modes in Photonic Molecules

“…In the present structures the resonator cavity for the photons has a size of approximately one light wavelength and was formed by a GaAs layer surrounded by highly reflecting GaAs͞AlAs Bragg mirrors [13]. A 7 nm wide In 0.14 Ga 0.86 As quantum well, which acts as the optically active medium, was placed in the center of the GaAs cavity [14].…”

“…A 7 nm wide In 0.14 Ga 0.86 As quantum well, which acts as the optically active medium, was placed in the center of the GaAs cavity [14]. Photonic molecules were fabricated by lithographic patterning of this cavity [13]. The structures were etched through the top mirror and through the GaAs layer, and the bottom mirror remained essentially unetched.…”

Photonic dot structure which emits photons horizontally to a built-in waveguide

“…For example, the PD proposed in the early stage was a mesa-etched quantum well having multilayered Bragg mirrors in the vertical direction [1]. Remarkable success in single-photon generation has been achieved with quantum dots in the vertical micro-cavity using multi-layered mirrors [2].…”