Solid State Lasers and Applications Proposed for Brookhaven’s ATF-II Marcus Babzien –BNL Igor Pogorelsky – BNL Mikhail Polyanskiy -BNL

Outline ATF/ATF-II Introduction Facility Laser Systems Laser Details History, capabilities, future goals Facility Laser Systems Overview, motivation Laser Details Photocathode Drive Laser Pulse Train Laser Strong Field Laser 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

ATF-II Introduction 8/1/16 ATF-II Solid State Lasers and Applications - M. Babzien

ATF: A National User Facility Designated a DOE National User Facility in 2015 https://www.bnl.gov/bnlweb/pubaf/fact_sheet/pdf/FS-ATF.pdf Capabilities in: Novel particle acceleration techniques R&D for smaller, more cost effective accelerators including: Plasma and dielectric wakefield acceleration Direct laser acceleration Inverse free-electron lasers and more… High-brightness radiation sources New techniques to produce electromagnetic radiation from THz to X-rays: FEL R&D Inverse Compton scattering THz radiation from dielectric structures and more… Beam manipulation and beam instrumentation Sophisticated longitudinal and transverse beam manipulation capabilities Wide range of beam parameters enabling development and testing of advanced accelerator hardware, beam diagnostics and detectors Ion generation and acceleration Experimental hardware for producing supersonic hydrogen gas jets provides capabilities for generating mono-energetic multi-MeV proton beams 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

ATF: A National User Facility Some facility facts: In operation for users since 1992 Scientific R&D Technology Demonstrations Accelerator Capability Development 39 graduate degrees from the program with 8 more pending Features: A high-brightness 80-MeV Linac A 2 TW picosecond CO2 laser system And now an Ultrafast Electron Diffraction facility Provides: A highly trained staff to support a broad array of user experiments A wide variety of experimental tools including those for laser-electron beam interactions The ability to do beam-based, laser-based and combined-capability research 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

ATF-II: Our Vision LINAC Gun ATF-II in BNL Bldg. 912 To provide a facility for advanced accelerator R&D that: Builds on the cutting edge science produced at the ATF for the last 25 years Provides world-leading scientific and accelerator technology output for the next 25 years RF & Electronics Equipment Room Experimental Hall #2 Experimental Hall #1 Pulse Train Laser CO2 & Strong Field Lasers + Experimental Area LINAC Gun Ultrafast Electron Diffraction and Drive Laser Room Electron Gun & Linac 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Facility Laser Overview 8/1/16 ATF-II Solid State Lasers and Applications - M. Babzien

Facility Lasers Overview Construct vacuum transport lines for flexible beam delivery of multiple lasers throughout facility L4 GH L1 LE L2 H1 L3 Pulse Train Laser CO2 & Strong Field Lasers Drive Laser 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Facility Lasers Overview The novel ATF short-pulse CO2 laser upgraded to higher power will continue to enable a unique experimental program ATF-II will provide gas and solid state lasers both for facility operation and experimental use, as does ATF However, it will utilize 4 independent laser systems for single bunch and pulse train operation of the photoinjector, and for experimental purposes Provides for an overall increase in capabilities Shrinks the parameter space of each system and allows better optimization Provides some level of redundancy Reduces operations impact of maintenance and future laser upgrades System Wave-lengths Temporal Format Repetition Rate Energy, Ppeak Example Applications CO2 9.2-10.6 mm 1x 2 ps 0.2 Hz 50 J, 25 TW Ion Generation, LWFA, Compton Scattering Photocathode driver 785 (262) nm 1x 100 fs 240 Hz 20 mJ, 200 MW ATF-II RF gun UED RF gun Pulsetrain 1064, (532), (266) nm 1-100x 14 ps < 10 Hz Multiple pulse Compton scattering cavity Strong Field 1x 50 fs 150 mJ, 3TW Two-color Compton, Two-color Ionization Injection LWA, Plasma interferometry & holography, Laser plasma shaping 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Facility Lasers Overview Effective laser strength for interactions may scale as l or l2 for many advanced accelerator mechanisms CO2 laser at 10 um attractive (see M. Polyanskiy, this WG, Thursday afternoon) 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Facility Lasers Overview By offering a variety of laser capabilities, the experimental configurations increases and enable new opportunities Wavelength coverage spanning 0.26 to 10 mm: e.g. Enables probing of wide range of LWPA plasma densities Femtosecond to picosecond pulse durations have useful temporal durations and spectral bandwidths Independently phased to each other and e-beam 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Photocathode Drive Laser 8/1/16 ATF-II Solid State Lasers and Applications - M. Babzien

Photocathode Drive Laser Drive Laser Room 8/1/16 ATF-II Solid State Lasers and Applications - M. Babzien

Photocathode Drive Laser Ti:Al2O3 regen -> single output pulse High repetition rate permits interleaved operation of multiple guns UV for linac & UED guns, IR for UED target Pulse shaping improvements for photocathode operation enabled by extra bandwidth and higher energy Electronic synchronization will give advantages in experiment setup IR Pulse Duration 100 fs Repetition Rate 240 Hz Pulse Energy 20 mJ (UV) Stability <1% RMS Beam profile M2<1.4 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Photocathode Drive Laser Pulse stacking limits attainable profiles to near-uniform, but is easy to align, optimize, and maintain Birefringent wedges allow larger dynamic range of pulse delays at each stage Tsinghua University a-BBO stacking 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Pulse Train Laser 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Pulse Train Laser Pulse Train Laser 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Pulse Train Laser High Reliability High performance Typical utilization & availability is >80% of BNL workdays Turn on time <15 minutes to full stability Laser physicist not required for turn on/off & experimental runs High performance Energy on cathode ~0.5% RMS stability Pointing stability 0.3% of beam diameter Timing jitter 0.2ps Trains up to 100 micropulses 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Linac Pulse Train Operation Pulse Train Laser Linac Pulse Train Operation Pockels Cell Modulator Combine into one Novel laser architecture mitigates gain depletion throughout pulse train & operates in conjunction with RF feedforward Demonstrated & used extensively in FEL oscillator experiment ca. 1997, and again in 2011-2012 for Radiabeam ICS experiment Produce up to 100 pulses flat within 5% AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Pulse Train Laser Useful for cavity–enhancement experiments Increases average power in e-beam signal-limited experiments Dual e-beam generation (independently phased drive & witness) Alignment of optical cavities (ring-up/down), radiation emulation for experimental diagnostics Energy: (dual pulse mode) Transverse Distribution: UV on cathode 0-30 mJ x 1 pulse Range of beam size on cathode (Ø) 0.2 - 3 mm IR to CO2 laser 10 mJ x 2 pulses Top-Hat Beam Profile Modulation (P-P) <50% Laser output: total IR 30 mJ IR to gun 7.5 mJ Repetition rate 1.5, 3 Hz Green 2.5 mJ UV 500 mJ Shot-to-shot stability (rms): Timing <0.2 ps Energy: (pulse train mode) IR ~100 mJ / 20 pulses Energy <0.8 % Pointing (fraction of beam Ø) <0.3 % Pulse duration (FWHM): Oscillator IR 7 ps Drift (8 hour P-P) Amplified IR 14 ps <15 ps 10 ps <5% 8 ps <1% 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Strong Field Laser 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Strong Field Laser Strong Field Laser 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

MOPA with three multi-pass amplifiers for TW peak power levels Strong Field Laser MOPA with three multi-pass amplifiers for TW peak power levels DAZZLER for dispersion management Maintain beam profile for optimal focusing at interaction point System has been operated and is in storage awaiting laser room completion 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Strong Field Laser SFL Design Parameters Pulse parameter Value Energy [J] <0.15 Pulse duration FWHM [fs] <50 Peak power [TW] <3 Central wavelength [nm] 815 M2 <1.5 Focused with f/10 optics:   peak intensity [W/cm2] ~5x1017 dimensionless strength parameter a0 ~0.5 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Strong Field Laser Applications: Two-color Compton scattering (TW or greater peak power) Y. Sakai et. al, Phys. Rev. ST Accel. Beams Vo. 14, 120702 (2011) Utilize two widely-separated wavelengths to generate complex electron trajectory and modify X-ray spectrum 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Strong Field Laser Applications: Ion generation plasma shaping (energetic NIR pulse) Two-color Compton scattering (TW or greater peak power) Y. Sakai et. al, Phys. Rev. ST Accel. Beams Vo. 14, 120702 (2011) FEL seeding (transform-limited pulse) Plasma wakefield holography (femtosecond, nm-bandwidth pulse) Plasma interometry,shadowgraphy Two-color ionization injection LWA (Trojan Horse) 8/1/16 AAC2016: ATF-II Solid State Lasers and Applications - M. Babzien

Most already implemented, integration needed Conclusion Wide variety of solid state laser beams will be available for ATF-II experimental program Most already implemented, integration needed New experiments & beam applications sought! 8/1/16 ATF-II Solid State Lasers and Applications - M. Babzien