Third harmonic generation in a Quantum Cascade laser with monolithically integrated resonant optical nonlinearity.

Area of Science:

• Quantum optics
• Semiconductor lasers
• Nonlinear optics

Background:

• Quantum Cascade Lasers (QCLs) are semiconductor devices emitting infrared light.
• Nonlinear optical processes enable frequency conversion of laser light.
• Third harmonic generation (THG) is a third-order nonlinear process.

Purpose of the Study:

• To demonstrate third harmonic generation (THG) in an InGaAs/AlInAs Quantum Cascade Laser (QCL).
• To investigate nonlinear optical properties of a novel QCL active region.
• To achieve frequency conversion in mid-infrared QCLs.

Main Methods:

• Fabrication of an InGaAs/AlInAs QCL with a three-well diagonal transition active region.
• Integration of a third-order nonlinear oscillator within the QCL.
• Characterization of optical output including pump radiation and generated harmonics.

Main Results:

• Successful demonstration of THG at approximately 3.7 mum from a pump source at 11.1 mum.
• Observation of second harmonic generation (SHG) at approximately 5.4 mum.
• The QCL design facilitated efficient nonlinear frequency conversion.

Conclusions:

• The presented InGaAs/AlInAs QCL design enables efficient third harmonic generation.
• This work expands the frequency conversion capabilities of quantum cascade lasers.
• The integrated nonlinear oscillator offers a novel approach for THz-wave generation and manipulation.