extremeultraviolet

Extreme ultraviolet (EUV) refers to the portion of the electromagnetic spectrum with wavelengths roughly from 10 to 121 nanometers, corresponding to photon energies from about 10 eV to over 100 eV. EUV lies between the far ultraviolet and soft X-rays and is strongly absorbed by air, so practical work requires vacuum conditions or inert gas environments. In astronomy and solar physics, EUV is used to study hot plasmas such as the solar corona and other high-temperature astrophysical environments. Space-based observatories and instruments provide imaging and spectroscopy in this range, often using grazing-incidence optics and specially engineered multilayer mirrors.

In industry and research, EUV is central to lithography for semiconductor manufacturing, particularly at around 13.5 nm. This application demands coherent light sources, extreme precision optics, and contamination control. Two main generation approaches are used: laser-produced plasma sources (commonly tin or xenon plasmas) and high harmonic generation from ultrafast lasers, along with synchrotron radiation in some contexts.

Detection and instrumentation for EUV employ detectors such as microchannel plates and back-illuminated sensors designed for low reflectivity and high quantum efficiency in the EUV range. Materials interactions are highly absorptive in this band, so most surfaces require specialized coatings and vacuum-compatible components.

Challenges include generating bright, stable EUV sources, maintaining high reflectivity mirrors, and developing resists and processes for EUV lithography. Ongoing research aims to extend source efficiency, improve optics, and broaden scientific and industrial applications while addressing safety and environmental concerns related to high-energy photons and vacuum operation.