Capillary discharge lasers are the highest average power tabletop coherent EUV sources presently available. These lasers have drastically reduced their size since their initial demonstration at Colorado State University in 1994. Today compact, high-repetition rate EUV lasers operating in the high-saturation regime open the opportunity to conduct experiments with intense, coherent EUV light on a table-top.
In these lasers, the light beam amplification is generated by fast discharge excitation of an Ar-filled capillary tube. The magnetic force of the current pulse and large thermal pressure gradients near the wall rapidly compress the plasma to form a dense and hot column with a large density of Ne-like ions. The compressed column has a very high axial uniformity and a length-to-diameter ratio of the order of 1000:1. Collisional electron impact excitation of the ground state Ne-like ions produces a population inversion between 3p and 3s levels, resulting in laser amplification at 46.9 nm.
Our most compact source is a desktop size pulsed laser at 46.9 nm.
General specifications for this system are as follows:
- Wavelength: 46.9 nm (26.5 eV photon energy)
- Pulse energy: 10 µJ / pulse
- Average power: 0.1 mW
- Pulse duration: ~ 1.5 ns
- Repetition rate: up to 10 Hz
- Divergence: ~ 5 mrad
- Monochromaticity: Δλ/λ < 1x10-4
Fast, short wavelength pulses allow capturing the motion of objects at the nanometer scale. In this work, a sequence of real-space flash images acquired with a table-top SXR laser was used to capture the motion of a rapidly oscillating magnetic nanoprobe.
Read more: S. Carbajo et al., Opt. Lett. 37, 2994 (2012).
Ablation of holes with diameters as small as 82 nm and very clean walls was obtained in poly(methyl methacrylate) focusing pulses from a Ne-like Ar 46.9 nm compact capillary-discharge laser with a freestanding Fresnel zone plate diffracting into third order.
Read more: G. Vaschenko et al., Opt. Lett. 31 , 3615, (2006).
High photon energy allows single photon ionization, which avoids molecule and cluster fragmentation.
Read more: S. Heinbuch et al., Journal of the Optical Society of America B 26, B85 (2008); S.G. He et al., J. Phys. Chem A 112, 11067 (2008).