Wafer-bonded coupled multilayer cavity with InAs quantum dots for two-color emission

Abstract

A GaAs/AlAs coupled multilayer cavity structure with InAs quantum dots (QDs) was fabricated by wafer-bonding of two cavity structures grown individually. The wafer-bonding technique is important to control the spatial distribution of nonlinear polarization for strong terahertz emission by the differential frequency generation of the two cavity modes of the coupled cavity. Three layers of self-assembled InAs QDs were inserted in a cavity grown on a (001) GaAs substrate as optical gain materials for two-color emission of the cavity mode lights. The other cavity with a GaAs cavity layer was grown on a (113)B GaAs substrate. Two-color emissions with a 3.8 THz frequency difference were successfully observed from the wafer-bonded coupled cavity by cw optical pumping at room temperature.

Effect of cavity-layer thicknesses on two-color emission in coupled multilayer cavities with InAs quantum dots

“…27) We also fabricated a GaAs=AlAs coupled multilayer cavity structure with InAs QDs by the surface-activated bonding method 28,29) of two cavity structures grown individually, and two-color emissions were successfully demonstrated by optical pumping. 30) However, neither emission property had a value desirable as the value of the optical frequency difference. The value was larger than that of the designed structure.…”

Time-resolved measurements of two-color laser light emitted from GaAs/AlGaAs-coupled multilayer cavity

“…Therefore, the InGaAs QWs in the upper cavity as optical gain materials were grown in an (001) orientation and had a high quantum efficiency. In contrast, the lower side of the structure was epitaxially grown on a 3 inch diameter (113)-oriented GaAs substrate by MBE Therefore, the lower cavity was also grown in an (113) orientation and had a non-zero second-order nonlinear susceptibility χ (2) for the light propagating in the [113] direction, 10,11) whereas the upper cavity had a zero secondorder nonlinear susceptibility. The non-zero second-order nonlinear susceptibility used in the lower cavity is required to generate THz waves in the DFG scheme.…”

“…8,9) We also proposed an original THz emitter possessing a GaAs/AlAs-coupled multilayer cavity structure. [10][11][12][13][14][15][16][17] The compact device had two cavities and three distributed Bragg reflectors (DBRs), and had gain layers in the one of the cavities. By contrast, in the other cavity, DFG of the two-color laser produced in the device was performed, where the generated electromagnetic waves then exhibited THz-wave properties.…”

Room-temperature two-color lasing by current injection into a GaAs/AlGaAs coupled multilayer cavity fabricated by wafer bonding

“…Two mode emission characteristics in the nearinfrared region have been studied by the optical pumping of self-assembled InAs quantum dots (QDs) that were introduced only in the upper cavity. [25][26][27] We have also fabricated current-injection surface-emitting devices based on a waferbonded coupled cavity with QDs. Although we introduced nine layers of InAs QD in the active region, the lasing action has not been realized yet owing to insufficient optical gain.…”