Overview of diode pumped high energy solid state lasers

Seite 1 F. Röser ■ [email protected] ■ www.hzdr.de ■ HZDR

Overview of diode pumped high energy solid state lasers

F. Röser, M. Löser, D. Albach, M. Siebold, U. Schramm, R. Sauerbrey Helmholtz-Zentrum Dresden-Rossendorf (HZDR)


Overview

High-Energy class diode-pumped solid state lasers

Projects worldwide

PENELOPE Project

Motivation – Laser driven ion therapy

Project description & status


High-power laser diodes:

+ up to 60% electrical-to-optical

efficiency

+ reduced heat into the laser medium

+ 1000× higher brightness than lamps

+ liftime: 1Gshot

(i.e. 10a@10Hz, 200d/a, 10h/d)

Diode-pumping

- Price ($/W)

mailto:10a@10Hz


High-energy class (HEC-) DPSSLs


HEC-DPSSLs: MERCURY

Yb:S-FAP, 60J, 10Hz, 12% + high efficiency at room temperature + longitudinal pumping & cooling + distributed bulk laser + high gain material – sophisticated gas cooling – exotic gain medium – large quantum defect


HEC-DPSSLs: MERCURY


DiPOLE high-energy amplifier

HEC-DPSSLs: DIPOLE

cryo Yb:YAG, 7J, 10Hz, 20%


HEC-DPSSLs: HALNA

Nd:glass, 22J, 10Hz, 12% + high efficiency at room temperature + large volume gain medium available + no reabsorption at room temperature + high gain material – short fluorescence lifetime of Nd – large quantum defect – transverse pumping – 1D aperture/energy scaling


HEC-DPSSLs: HALNA


HEC-DPSSLs: GENBU

Yb:YAG, 200mJ, 100Hz, 30% + high efficiency + longitudinal cooling + multiple active mirrors – cryo cooling – energy/aperture scaling limits


HEC-DPSSLs: GENBU


HEC-DPSSLs: LUCIA

Yb:YAG, 14J, 2Hz, 12% + room temperature operation + active mirror concept + gradient doping option + energy scaling option at multiple active mirrors – water cooling (jet plate)


HEC-DPSSLs: LUCIA


HEC-DPSSLs: HILASE-Prague/LWS Munich

Yb:YAG thin-disk + room temperature operation + commercial thin-disk technology – low gain – energy scaling limited due to ASE – up to 1J feasible


HEC-DPSSLs: POLARIS-Jena


HEC-DPSSLs: POLARIS-Jena

Yb:glass, 16J, 0.01Hz, 5% + room temperature operation + broad bandwidth (~15nm) operation – low efficiency due to reabsorption – low rep-rate – 940nm pumping (instead of 980nm) – bulk laser design – brightness losing pump engine – transverse cooling

Yb:CaF2, 400mJ, 1Hz, 3% + relay imaging cavity + possibly high efficiency + 940nm pumping (no diode stabilazation) – cryo / vacuum technology – narrowed bandwidth – bulk laser design – transverse cooling


Overview


Projects worldwide

PENELOPE Project




future: compact proton accelerators for radiation therapy


0 10 20 300

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Protonen

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Eindringtiefe in Wasser / cm

Photonen

0 10 20 300

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Protonen

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Photonen

0 10 20 300

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Protonen

No

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Photonen

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Photonen

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Photonen

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Photonen

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Protonen

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Photonen

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Photonen

0 10 20 300

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Protonen

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Photonen

0 10 20 300

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Protonen

No

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Photonen

0 10 20 300

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Protonen

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Photonen

0 10 20 300

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(175-190 MeV)Protonen

Protonen

No

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Photonen

healthy tissue tumor

Penetration depth in water [cm]

No

rma

lize

d d

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e



© GSI Darmstadt

Localized dose deposition for

precise tumour treatment

Benefitial for 10-20% of patients

Conventional ion therapy

Large scale/costly setup:

accelerator, beam guidance &

radiation shielding

Laser driven ion therapy

Pro

ton

nu

mb

er

Time

1 s

~1 ns

high acceleration

gradients TV/m

compact source and

laser beam transport

1010 to 1013 ions per pulse

Short ion pulses: fs to ps at the

source

Broad energy spectrum

Facility Image courtesy by Stern, Gruner+Jahr AG & Co KG, Germany Dose Image courtesy by O. Jäkel, DKFZ Heidelberg, Germany


Basic research High pulse dose rate radiation

Biological effectiveness?

Clinical practice Laser driven dose delivery system

Stable & reliable laser proton accelerator

Precise beam delivery: Spatial & spectral shaping

Real-time dosimetry

Translational Research - Concept

Laser / plasma development

100

depth in water [cm]

• Proton energy Increase

• not monoenergetic, but sufficiently high

rela

tive e

ffective d

ose [%

]

Clinical trials

In vitro - cells

In vivo - animals


Center for high power radiation sources

Start in summer 2010

Building finished in summer 2011



2012 - New lab space (800 m2): clean rooms – workshop – cell lab

Footprint of the extended ELBE (electron accelerator) building



DRACO Laser (Ti:Sa, 4J in 30fs -> ~150TW) and ion acceleration area



2013: DRACO Upgrade

Dual ultra-short pulse beam option (50TW / 500TW)) (~1.5/15J in 30fs)



~2014/15 - PEnELOPE 150J in <150fs, >1Hz rep rate active medium (Yb:CaF2) fully diode pumped system

Petawatt, Energy-Efficient Laser for Optical Plasma Experiments


OGZ – joint center for radiation research

experimental cave

43 m

las

er-d

riven

Conventional proton therapy facility (patient treatment start 2014)

+ unique benchmarking option for in-house laser accelerator

direct comparison to conventional proton beam


Overview


Projects worldwide

PENELOPE Project




Front end: 1) single CPA 2a) double CPA + XPW 2b) OPCPA +pump laser up to 10J (Yb:YAG)

Goal: 150J, <150fs, 1Hz, >5% o-o eff.

Layout


Laboratory infrastructure

Tables: 90m²

Lab space: 340m2


Footprint & current status


Amplifier Design – Multi Slab approach

→ tested at 60J, 10Hz (LLNL) & 10J, 6Hz (RAL) → low thermal abberations → operation at RT + MP pumping possible → solid angle for pump & extraction: 4p instead of 2p → 4 slabs 110 mm diameter, thickness: 5mm

[K. Ertel et.al. Opt. Express 27, 26610 (2011)]


Amplifier Design – Final amplifier stage

2 × 600kW


Amplifier Design – Brightness Requirement

(7.5“ @ 200J)


Compressor

dielectric gratings (PGL) 940 × 420 mm²

1760 lines/mm, ~0.5 J/cm2

Beam diameter: 250mm

Dimensions: 6 × 3 × 1.5 m3

(~15k€/m3 vacuum)


Conclusions

Today:

Worldwide high energy projects push laser and optics technology, but limited

in repetition rate/average power due to heat dissipation timescales

Dresden program for laser driven proton therapy with prototype diode

pumped PW laser system PEnELOPE.

Future:

ICAN concept - significant repetition rate scaling

ICAN laser profits from experience of large single beam lasers in terms of

laser technology, e.g. contrast control, pulse shaping&control, high power

optics development

Documents

Overview of diode pumped high energy solid state lasers