Ultra-fast amplitude modulation of mid-IR free-space beams at room-temperature

Abstract

Applications relying on mid-infrared radiation (Mid-IR, $\lambda \sim$ 3-30 $\mu$m) have progressed at a very rapid pace in recent years, stimulated by scientific and technological breakthroughs. Mid-IR cameras have propelled the field of thermal imaging. And the invention of the quantum cascade laser (QCL) has been a milestone, making compact, semiconductor-based mid-IR lasers available to a vast range of applications. All the recent breakthrough advances stemmed from the development of a transformative technology. In addition to the generation and detection of light, a key functionality for most photonics systems is the electrical control of the amplitude and/or phase of an optical beam at ultra-fast rates (GHz or more). However, standalone, broadband, integrated modulators are missing from the toolbox of present mid-IR photonics integrated circuits and systems developers. We have developed a free-space amplitude modulator for mid-IR radiation ($\lambda \sim$ 10 $\mu$m) that can operate up to at least 1.5 GHz (-3dB cut-off at $\sim$ 750 MHz) and at room-temperature. The device relies on a semiconductor hetero-structure enclosed in a judiciously designed metal-metal optical resonator. At zero bias, it operates in the strong light-matter coupling regime up to 300K. By applying an appropriate bias, the device transitions to the weak coupling regime. The large change in reflectivity due to the disappearance of the polaritonic states is exploited to modulate the intensity of a mid-IR continuous-wave laser up to speeds of more than 1.5 GHz.

References in corpus (1)

• Optical properties of metal-dielectric-metal microcavities in the THz frequency range

Cited by in corpus (11)

• Longitudinal piezoelectric resonant photoelastic modulator for efficient intensity modulation at megahertz frequencies
• Unified description of saturation and bistability of intersubband transitions in the weak and strong light-matter coupling regimes
• Low intensity saturation of an ISB transition by a mid-IR quantum cascade laser
• Modulation characteristics of uncooled graphene photodetectors
• Heterodyne coherent detection of phase modulation in a mid-infrared unipolar device
• Detection of strong light-matter interaction in a single nano-cavity with a thermal transducer
• Ultrafast (10 GHz) mid-IR modulator based on ultra-fast electrical switching of the light-matter coupling
• A "Janus" double sided mid-IR photodetector based on a MIM architecture
• Integrated thin film lithium niobate mid-infrared modulator
• An effective density matrix approach for intersubband plasmons coupled to a cavity field: electrical extraction/injection of intersubband polaritons
• Direct polariton-to-electron tunneling in quantum cascade detectors operating in the strong light-matter coupling regime