ICAN meeting, Palaiseau, 11/10/2012 Some temporal aspects of Passive cavity-dumped enhancement for ICAN

Transcription

1 ICAN meeting, Palaiseau, // Some tempoal aspects of Passive ity-dumped enhancement fo ICAN Laboatoie Chales Faby, Institut d Optique, Palaiseau

2 Passive ity-dumped enhancement pinciple Repetition ate convete Enegy concentato Diffeent fom standad passive ity enhancement: the pulse is dumped befoe the stationay state of the ity (maximum ciculating pulse enegy) is eached Passive ity enhancement Incoming lase pulses Intaity ciculating pulse builds up until stationnay state State of the at fo passive ity enhancement in steady-state egime : see next talks

3 Passive ity-dumped enhancement pinciple Repetition ate convete Enegy concentato Diffeent fom standad passive ity enhancement: the pulse is dumped befoe the stationay state of the ity (maximum ciculating pulse enegy) is eached Passive ity-dumped enhancement Intaity ciculating pulse builds up Incoming lase pulses Pulses ae switched out at submultiple of ep ate 3

4 Passive ity-dumping : state of the at Expeiments wee made in 4 mostly at JILA and MPQ - Stating fom Ti:Sa oscillatos (fs and ps) at ep ate ~ 8 MHz, using AO ity dumpe, some expeiments done with stetche/compesso - Enhancement factos between and 7 - Output epetition ate ~ 5 khz, Enegy efficiency always below 5% Issues - Spatial : mode matching, Ke lens - Stabilization : esidual phase noise - Tempoal : ity dispesion and nonlineaity Jones et al., «Femtosecond pulse amplification by coheent addition in a passive optical ity» OL Jones et al., «High-epetition-ate coheent femtosecond pulse amplification with an extenal passive optical ity» OL 4 Potma et al. «Picosecond-pulse amplification with an extenal passive optical ity OL 3 Vidne et al. Pulse picking by phase-coheent additive pulse geneation in an extenal ity OL 3 4

5 Enhancement and efficiency Input couple t Rest of ity E in E cic t Enhancement : atio of ciculating pulse enegy to input pulse enegy ( n) E cic / E in t t n t when n Efficiency : atio of ciculating pulse enegy to sum of input pulse enegies ( n) E cic / ne in n t t n when n 5

6 Enhancement Enhancement and efficiency Efficiency Input couple t Rest of ity E in E cic t Example fo t =99.99% - Maximum enhancement obtained with =t (t =.%) is α=. In this case, the maximum efficiency is η=.4 fo stacked pulses - Fo a fixed value of 6 stacked pulses, maximum enegy efficiency is η=.8 obtained fo t =.4%. In this case the stationay enhancement is α= Numbe of pulses 5 5 Numbe of pulses 6

7 Enhancement Maximum efficiency Efficiency Input couple t Rest of ity E in E cic t Analytical estimate of maximum efficiency fo a pefect ity t n nln t Numbe of pulses Numbe of pulses 7

8 Dynamics: Numeical model Pulse buildup in the ity by altenating. Coheent addition of input pulse though the couple. Popagation of pulse though the ity Simila to split-step Fouie popagation algoithm Input couple E in E cic Dispesion, Self-phase modulation K.D. Moll, R. Jason Jones, and Jun Ye, Nonlinea dynamics inside femtosecond enhancement ities, Opt. Exp. 5, 67, 5. 8

9 Enhancement Efficiency Numeical model: example Intensity Intensity Example fo t =99.99%, t =.4% + Dispesion -φ =4 fs pe oundtip -φ 3 = fs 3 pe oundtip 6 + Self-phase modulation - Equivalent to µm thickness of glass with a beam diamete of mm Numbe of pulses Time (ns) Numbe of pulses Fequency (THz) 9

10 Conclusion Numeical dynamic passive ity dumped enhancement model that takes into account - Dispesion - Nonlinea effects - Residual fluctuations of f ep and f CEO Tool fo subsystem design : adaptive ity detuning, intensity shape, etc Add spatial aspects?

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