Lightwave-Driven Long-Wavelength Photomultipliers

A novel lightwave-driven detector that combines photomultiplier tube (PMT) technology with structured metasurfaces is presented to enable efficient detection of long-wavelength radiation in the mid-infrared (mid-IR) to terahertz (THz) range. This overcomes the limitations of conventional PMT technology, which cannot efficiently detect wavelengths longer than 1.7 & mu;$\umu$m. The approach utilizes the long-wavelength radiation's instantaneous electric field to facilitate field-driven electron emission from metasurfaces, which allows it to cover the entire THz to mid-IR range by geometric scaling. This enables a novel class of lightwave-driven detectors with the benefits and performance characteristics known from the established PMT technology, such as fast response times and low noise, while expanding the operational wavelength range vastly. It is shown that the amount of field-emitted electrons depends on the THz electric field in a highly nonlinear manner, generally following the Fowler-Nordheim relation. Furthermore, the THz-PMT can determine specific lightwave characteristics of the incident field, including its peak field strength and absolute polarity, due to its sensitivity to the sign of the electric field. With a field sensitivity as low as a few kV cm-1, the THz-PMTs provide a versatile tool for high sensitivity detection across various fields of interest in science and technology. A novel class of long-wavelength lightwave detectors is demonstrated. The detector is based on using a metasurface as the photocathode in a photomultiplier tube. This changes the fundamental physical principle for electron emission from the photoelectric effect and into a field emission effect. As a result, incident photons can have arbitrarily low photon energy and still be detected.image

Automated summary

A novel lightwave-driven detector that combines photomultiplier tube (PMT) technology with structured metasurfaces is presented for efficient detection of long-wavelength radiation. By utilizing the long-wavelength radiation's electric field, the detector can cover the entire terahertz to mid-infrared range by geometric scaling, overcoming the limitations of conventional PMT technology. The detector provides fast response times, low noise, and the ability to determine specific lightwave characteristics, making it a versatile tool in science and technology.