Response Time-Shortened Zinc Oxide Scintillator for Accurate Single-Shot Synchronization of Extreme Ultraviolet Free-Electron Laser and Short-Pulse Laser

Abstract

We report an over one-order-of magnitude improvement in the response time of conventional hydrothermal method-grown zinc oxide (ZnO) scintillator by introducing additional quenching channels via intentional indium ion doping. A 3-ps fluorescence decay time constant is achieved, therefore making it the fastest scintillator operating below 100 nm to date. Using this indium-doped ZnO, relative jitter between extreme ultraviolet free electron laser (EUV-FEL) probe and optical pump pulses is evaluated to be less than 3 ps. Moreover, pulses from these sources can be synchronized with 3-ps accuracy through in-situ observation of relative time difference in single-shot base.

Soft x-ray free-electron laser induced damage to inorganic scintillators

“…Single crystals of PbWO 4 and Ce:YAG were grown from high-temperature melt of the corresponding material using the Czochralski technique [16,17] while monocrystalline ZnO was prepared by a conventional hydro-thermal technique [7].…”

“…The scintillator properties required for short-wavelength laser beam characterization and imaging are as follows: a high yield of luminescence, a well-defined dependence of the yield on radiation properties (e.g., well-known dependence of the yield as a function of radiation intensity) fast response to the ultra-short laser pulses, sufficiently high absorption coefficient and damage threshold. For example, PbWO 4 [5,6] or ZnO [7] single crystals, with decay times of 2-3 ns and less than 1 ns (down to a few picoseconds dependent on doping concentration), respectively, can be used for detecting, timing and imaging short and ultra-short pulses of x-ray lasers [1][2][3][4]. The third material chosen for our experiment, Ce:YAG (Ce:Y 3 Al 5 O 12 ) crystal, is widely used for the soft X-ray laser beam imaging and characterization because of its high luminescent yield and excellent radiation resistance [8][9][10].…”

Optical properties of hydrothermal-method-grown ZnO crystal as EUV laser diagnostics material

“…Previous studies done on the effect of impurity doping on ZnO have shown that there is a compromise between decay time and fluorescence intensity. Because of the fluorescence quenching effect of the Fe-impurities, the faster decay time comes with weaker fluorescence intensity [11]. 3d transition metals such as Fe in other semiconductor materials are known to play the role of lifetime-shortening impurity.…”

Potential High-Spatial Resolution In-Situ Imaging of Soft X-Ray Laser Pulses With ZnO Crystal

“…Furthermore, we have succeeded in shortening its emission lifetime to less than 100 ps and its rise time to 10 ps by intentional Fe ion-doping. Results have also revealed the dependence of fluorescence intensity and decay time on the type of dopant ion [18]- [21].…”