Industrial Affiliates Workshop, Feb Femtosecond enhancement cavities for generation of light at extreme wavelengths R. Jason Jones College of Optical Sciences University of Arizona Graduate Student: James Johnson Funding: National Science Foundation

Research Interests… Ultrafast Optical Science Optical Frequency Metrology

Research Interests… Ultrafast Optical Science Optical Frequency Metrology Generation of coherent light at “extreme” wavelengths Precision spectroscopy in the vacuum ultraviolet  next generation atomic clocks  tests of fundamental physics e-e-

Research Interests… Ultrafast Optical Science fs State of the art until ~5 years ago

Research Interests… Ultrafast Optical Science <1 fs State of the art today…carrier phase control  attosecond timing dynamics  access to high electric field strengths  coherent addition and synthesis

Research Interests… Ultrafast Optical Science <1 fs State of the art today…carrier phase control  attosecond timing dynamics  access to high electric field strengths  coherent addition and synthesis laser

Research Interests… Ultrafast Optical Science <1 fs laser State of the art today…carrier phase control  attosecond timing dynamics  access to high electric field strengths  coherent addition and synthesis

Femtosecond enhancement cavities laser

Femtosecond enhancement cavities laser Xenon Plasma

Femtosecond enhancement cavities laser spectroscopy Xenon Plasma

Femtosecond enhancement cavities laser spectroscopy Extreme Nonlinear optics Xenon Plasma

Nonlinear frequency upconversion in a dilute gas Harmonics generated into “soft” x-ray regime Microscopy and biological imaging (> 250 eV) EUV holography Nanolithography Attosecond pulse generation … Traditional method: Single pass with amplified pulse VUV light source

Femtosecond enhancement cavity - Ideally suited for HHG –Low intra-cavity losses (low conversion efficiency) –Power is “recycled” –Maintains high repetition rate

VUV light source Femtosecond enhancement cavity - Ideally suited for HHG –Low intra-cavity losses (low conversion efficiency) –Power is “recycled” –Maintains high repetition rate 3rd harmonic (266 nm) 5th harmonic (160 nm) 7th harmonic (114 nm)

Gas jet Focusing mirror drilled mirrorCoherent EUV light Higher-order cavity mode VUV light source

- TEM 0,1 mode - ~ 275 micron hole Numerical calculations fs enhancement cavities with higher-order spatial modes Hole diameter (microns) Loss Cavity loss L~ 0.16%

2-color femtosecond enhancement cavities fs laser 2fs laser 1 FEC chamber Coherent pulse synthesis Efficient HHG Terahertz Generation

Summary Femtosecond enhancement cavities  High-field nonlinear optics  Generation of coherent light at extreme wavelengths Precision spectroscopy in the vacuum-ultraviolet  Next generation optical clocks  Precision tests of fundamental physics

Precision tests of fundamental physics Hydrogen: 1S-2S, 243 nm (Hänsch et. al.) Helium: 1 1 S- 2 1 P, 58.4 nm (Hogervorst, Ubachs et.al.) 1 1 S- 2 1 S, 120 nm ( Eyler et. al.) High-resolution spectroscopy of multi-electron atoms (compare with quantum-defect theory) Xenon: 105 nm (Ubachs et. al., 2001) Krypton: 88 nm (Bellini et al, 2002) 212 nm (Eikema et. al., 2005) Applications Extreme-UV atomic clocks Efficient production of metastable states e.g. atomic lithography e-e- Precision spectroscopy in the vacuum-ultraviolet