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Mercury. Modeling efforts on the Mercury Laser system. Andy Bayramian, Camille Bibeau, Ray Beach Prop ’92 work: Ron White French Collaboration with MIRO:Olivier Morice, Bruno Legarrac, Marc Nicolaizeau, Xavier Ribeyre.
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Mercury Modeling efforts on the Mercury Laser system Andy Bayramian, Camille Bibeau, Ray Beach Prop ’92 work: Ron White French Collaboration with MIRO:Olivier Morice, Bruno Legarrac, Marc Nicolaizeau, Xavier Ribeyre
Comparison of important spectroscopic and thermal properties between pertinent laser host / dopants Yb:S-FAP has the unique property of high cross sections and long lifetime allowing efficient pumping and extraction with a minimum number of diodes The low saturation fluence in S-FAP allows efficient extraction below typical material damage thresholds UCRL-PRES-146219
Calculation of gain Pump Equations: Gain/Extraction Equations: (Franz-Nodvik) • Feathered doping to equilibrate the gain through the amplifier head • Symmetric pumping from left and right sides make gain profiles symmetric about center slab • 77% of the diode pump light is transferred from the diode backplanes to the extractable area of the amplifier • 13% of the diode pump light is transmitted through the amplifier due to pump saturation UCRL-PRES-146219
Transfer efficiency of the pump delivery system output matches optical modeling data He gas in Diode Array Hollow pump light homogenizer Laser beam Gas - cooled slabs Diode Array Hollow pump light concentrator UCRL-PRES-146219
The Mercury laser system minimizes damage by arranging the lenses, amplifiers, Pockels cell, and mirrors near relay planes Pockels Cell Reverser Front End Amplifier 1 Relay plane 1.5 x output telescope lens 3.5 meters Relay plane Relay plane Relay plane Relay plane Amplifier 2 Deformable Mirror UCRL-PRES-146219
The MIRO code uses the paraxial wave equation with full diffraction and an adaptive mesh, which allows accurate modelling of a beam through an image relayed system Advanced beam propagation modeling using MIRO a diffraction code developed by the French • MIRO results include: • F(x,y,z,t) • I(x,y,z,t) • Pulse shaping • B-integral UCRL-PRES-146219
Current Mercury models show promising results • Ein = 20 mJ, Eout = 83 J • Energy through • a 5X DL spot: 96.0% • a 1X DL spot: 81.2% • B-integral (5 ns): 0.7 radians • Using Dn = 300 GHz bandwidth requires increase injection: • Ein = 165 mJ, Eout = 85.0 J • Caveats to current modeling results • Amplifier phase files are simulations • Low frequency information lost due to small files • Arbitrarily randomized to simulate multiple slabs • Phase distortions on amplifiers only • Thermal distortions not included yet • Benchmarking in progress against Prop 92 and experiments UCRL-PRES-146219
B-Integral causes beam breakup as the pulswidth decreases below 1 ns 0.5 ns 1 ns 5 ns UCRL-PRES-146219
MIRO • OPTICAD: • architecture • delivery efficiency • multiplexing angle • VB 1D Pump: • 1-way 1D abs/slab • 1-way 1D gain/slab • VB 1D Extract: • 2-way 1D gain/slab • E, B-integral, t, h • ASE, power density • FIDAP: • Diffuser design OPTICAD: 1-way 2D pump light deposition/slab • TEXTAN: • Heat xfer coef. • Fritz VB process: • 2-way 2D gain/slab • 2D norm. source desc. • TOPAZ: • 2D temp. distribution • NIKE: • 2D map of stress • and displacement • ZEEMAX/CODE V: • Lense shape • AAA drawings • Expected wf error • ghost analysis • OPL: • 2D thermal OPL map • ASAP: • Pinhole sizes • Pencil beam analysis • OPL PLOT: • 2D thermal phase map • ASE: • Slab aperture limitations • and geometry • Edge cladding Experimental: Wavefront, input, and loss measurements code flow chart.ppt
Prop ’92 benchmarking of the MIRO code L5b L5a L5c L5d S1-S7 M5 Front End FS1 FS2 PC G = 2 uniform flattop Fsat = 3.0 J/cm2 Per slab Output Relay Plane Front end for first 4 propagations Energy = 0.1 J Wavelength = 1047 nm Temporal FWHM = 5 ns Time exponent = 50 Height FWHM = 2.8 cm Width FWHM = 4.8 cm Spatial exponent in X & Y = 20 • Currently benchmarking simple propagation such that Energy, intensity, phase, and B-integral match • Phase and gain files then added and re-verified • Optional: The full mercury system modeled UCRL-PRES-146219
Trivalent ytterbium shows high cross sections and long lifetime in the Sr5(PO4)3F (S-FAP) host sem = 6 x 10-20 cm2 sabs = 9 x 10-20 cm2 tem = 1.14 ms Absorption Emission UCRL-PRES-146219