dr martin richardson-the future of solid state lasers

8/3/2019 Dr Martin Richardson-The Future of Solid State Lasers

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The future of solid state lasers

Martin RichardsonTownes Laser Institute, College of Optics & Photonics

University of Central Florida, Orlando, [email protected]

June 21, 2011
mailto:[email protected]:[email protected]


2/31

The first laser a ruby laser

May 17, 1960


3/31

Vernueil ProcessCzochralski process

Q-switching the invention thatnearly killed it all!


4/31

The age of glass lasers

Flashlamp-pumped pulsed crystalline lasers eventually

limited by laser material size and damage threshold.

Crystal size limited by boule diameters. Dopant ~ 1%Maximum Nd:YAG rod diameter ~ 1 cm.Damage thresholds ~ 20 J/cms

Repetition rates 1- 10 Hz. Limited by heat deposition.

Nd- doped glass

Amplifiers use 3,072 42-kg neodymium-

doped phosphate glass slabs, measuring

3.4 by 46 by 81 cms


5/31

Solid state lasers at the end of the 80s

Flashlamp pumping kept commercial

solid state systems to low powers.

Largely pulsed regime.

Low repetition-rates, ~ 100s Hz

heating, flashlamp recycling time,

Low efficiencies (


6/31

Enter the 90s the age of diode pumping

808 nm pumping for Nd:YAG

..940 nm pumping for Yb:YAG even better

10.5% for Yb:YAG

LLNL 50 kW diode array

Average powers jump from 100Ws to KW

Efficiencies increase 100s fold to 20-30%

Renewed interest in crystalline lasers- 100 x higher thermal shock resistance- higher thermal conductivity


7/31

Trumpf

Diodes enable new pump architectures

Rod type architecture Thin disc architecture


8/31

JHPSL Northrop Grumman 100 kW SSDPL

To be deployed at HELSTF summer 2011


9/31

Trumpf markets 16 kW thin disc DP SSL

Trumpf


10/31

High power fiber lasersRapid development ofcommercial systems (IPG,

SPI, Nufern, )

Single mode powers of ~ 1kW.

BEAM COMBINING

Multiple beam tiling

Coherent Beam Combining

Spectral Beam Combining

25 kW

Nufern

SPI

IPG


11/31

Diode pumping also enabled SS ultrafast

CW DPSL (2) pumpedTi:Sapphire

Regenerative and multi-passTi:Sapphire amplifiers pumped byDP or flashlamp pumped SSls

Pulse durations 50 -500 fs

Pulse energies < 10 mJ

Repetition rates 1 kHz 100 kHz

Newport -Spectra

Coherent

Amplitude


12/31

The limits of todays technologies

High power SS lasersCreated a near-$B market in high power lasers for

manufacturing.Reaching limitations in high power architecture imposed by thermalloading and single crystal host.Beam quality and thermal loading primary constraints.Yb:YAG the most efficient SS laser material.Cryogenic Yb:YAG offering improvements in thermal dissipation.

High power fiber lasersRapid rise in high power fiber laser market ( $100Ms/year).Efficiency and cost important drivers.Mode size limiting maximum power.Component development (couplers, isolators..).

Ultrafast lasersTi:Sapphire based systems limited market penetration.Power (rep.rate), cost, complexity and efficiency.

Lack of identified single large market.


13/31

Tomorrow New transformative technologiesNew Laser Materials

Polycrystalline materials transparent ceramicsNew laser host materials. New SSL architecturesNew infra-red laser materials. High powers in the Mid IR

New Pump SourcesCurrently limited to near IR high power diodes

Visible and UV diode sourceshigh power 15XX nm and 19XX nm diode sources

New Fiber ArchitecturesLMA fiber designs. Holey fiber and HOM designsNew fiber preform and fabrications techniques

Next generation of ultrafast lasersFiber-based systems. Increased reliability, efficiencyReductions in cost, complexity, footprint.Manufacturing market-leverage development


14/31

Tomorrow New transformative technologiesNew Laser Materials

Polycrystalline materials transparent ceramicsNew laser host materials. New SSL architecturesNew infra-red laser materials. High powers in the Mid IR

New Pump SourcesCurrently limited to near IR high power diodes

Visible and UV diode sourceshigh power 15XX nm and 19XX nm diode sources

New Fiber ArchitecturesLMA fiber designs. Holey fiber and HOM designsNew fiber preform and fabrications techniques

Next generation of ultrafast lasersFiber-based systems. Increased reliability, efficiencyReductions in cost, complexity, footprint.Manufacturing market-leverage development

General trend to monolithic integrated functionality lightengines of the future


15/31

Single Crystal Growth

Goal: Single crystal

One large grain

No grain boundaries

Difficult to grow crystals from high temperature melt:

Compositional variations

Crucible interactions

Phase transitions (strain cracking)

Poor RE solubility and uniformity

Size limitations

Low yield

Cannot grow large crystals or complexshapes from best crystalline materials

Split

crack

High Temperature Growth from Melt

RE doped powder

Sinter/Densify

(Add sintering aid)

Grains containing

rare earth ions

Transparent Polycrystalline Ceramic

Many small grains

Grain boundaries

Hot Press

Gas

HIPRE doped powder

Sinter/Densify

(Add sintering aid)

Grains containing

rare earth ions

Grains containing

rare earth ions

Transparent Polycrystalline Ceramic

Many small grains

Grain boundaries

Hot Press

Gas

HIP

Ceramic Process

Low temperature (


16/31

Nano-powder synthesis

(wet-chemistry, spray pyrolysis)

Powder shaping

(cold pressing, slip casting)

Pressureless Sintering Field Assisted Sintering Hot-uniaxial pressing

Hot-Isostatic Pressing

(Ar, >150 MPa)

Post-sintering heat-treatments

(annealing, re-crystallization)

Powder handling

(de-agglomeration, blending)

Sinter-HIP

Binder burn-out, pre-sintering

CRITICAL STEPS

spinel

Fabrication of transparent laser ceramics


17/31

Milestones on the ceramic laser road67 kW

100 kW

2006 2011


18/31

Ceramic Nd:YAG large sizes- bonded materials

Konoshima

LLNL


19/31

1980 1985 1990 1995 2000 2005 2010

10-5

10-4

10-3

10-2

10-1

100

101

102

Attenuationcoefficie

nt(cm-1)

10-2

10-1

100

101

102

103

104

105

106

Maxim

umLaserPower(W)

Improvements in Nd:YAG ceramic laser power


20/31

Develop of ceramic laser materials will bedriven also by other applications.

Preliminary diffusion bonded SPINEL samples(3 x 3 x ) showing excellent bonding

Sangera, NRL

Large IR-transmittingwindows

Next generationnuclear scintillators

Medical imagingHomeland Security


21/31

Scintillator CeramicsScintillator Applications

Bruno Viana


22/31

Property Measurements Fused Silica OFG Glass SPINEL

Optical

Absorption Coefficient (ppm cm-1 at

1.06 m)

12 75 6

Refractive Index (at 1.06 m) 1.45 1.45 1.707

dn/dT (/K) at 633 nm 1.2x10-5 -9.2x10-6 2.3 x10-5

Stress Optic Coefficient (/Pa) 3.4x10-13 4.1x10-13 3x10-13

Mechanical

Density (g/cm3) 2.2 3.75 3.58

Poissons Ratio 0.17 0.31 0.27

Hardness (kg/mm2) 600 500 (est) 1645

Fracture Strength (MPa) 50 102 350

Youngs Modulus (GPa) 74.5 69.6 271

Thermal

Thermal Expansion Coeff. (/K) 0.5x10-6 14.9x10-6 5.9 x 10-6

Heat Capacity Cp (J/g/K) 0.74 0.67 0.604

Thermal Conductivity (W/(m.K) 1.38 0.7 13.4

SPINEL compared to Fused Silica: 2x lower absorption coefficient

> 2.5x harder and 7x stronger 10x higher thermal conductivity

Property Comparison with Other Materials

SPINEL compared to OFG glass: >10x lower absorption coefficient 3x stronger and > 3x harder 3x lower CTE 20x higher thermal conductivity

Aggawal & Sanghera


23/31

Engineered Laser Ceramics

Example of a non-uniform doping

Transverse doping profile geometry scalable to multiple kW

R. Gaume

Stanford


24/31

Engineered Laser Ceramics

Fabrication of dopant-engineered ceramics

Non-reactive sintering:

Cold-pressing, Slip-casting, Tape-casting

Ceramic ceramic bondingCeramic single crystal bonding

Bonding of bulk materials:

Reactive sintering:Cold-pressing, Slip-casting, Tape-casting

Courtesy of A. Ikesue

A i t i C i M t i l


25/31

Anisotropic Ceramic Materials- A new class of ceramics

Akayama, Sato & Tiara, Adv. Solid State Lasers, Denver 2009

Interaction between spin-orbit momentum of

f-electrons and host material under an

applied magnetic field.

Magnetic orientation of rare

earth-doped diamagnetic material

RE: Ca10(PO4)6F2 (RE:Nd, Yb) FAP

B

2 T

applied during

slip casting

Crystal orientation of ceramicsFor Yb:FAP (002) and (004) planes

corresponded to c-plane: (003) planecorresponded to a-planeFor Nd:FAP (003) plane correspondedto c-plane:

Absorption and Emission spectraStrongly axis-dependentc-axis/a-axis absorption coefft 1.3C-axis/a-axis emission ~ 1.43

N fib l t h l i


26/31

New fiber laser technologies

New fiber designs

NKT Photonics

For the future:100 kW class fiber lasers?High power mid- IR fiber laser?Polycrystalline (ceramic) fiber lasers?Single crystal fiber lasers?

New IR fiber lasers

High power tunable,

all-fiber 2mTm fiber laser.

C-R 790 nm pumping

200 pm linewidth

LPL, Townes InstituteNufern

Rod-type PCF fibers

New LMA fiber designs

N lt f t l


27/31

New ultra-fast lasers

Amplitude

IMRA

Raydiance

New GeometriesOPCPA systems. Hybrid amplifier technologies

Quasi- single cycle, CEP.

New compact high power fiber lasersRugged low cost systems

Initial niche market applications

Many new start-up companies

N l t t h l gi


28/31

New laser component technologies

5 mm

5 mm

Waveguide

Layer

Diffractive Array of

Holes

New high power dispersive optics

Volume Bragg gratings Glebov, Optigrate

Guided-mode

Resonant

Filters

Johnson, UNCC

Optics for phase control

Direction oftranslation

Focusing element

DOE Glass sample

Input writingbeam


Focusing element

DOE Glass sample

Input writingbeam


Focusing element

DOE Glass sample

Input writingbeam


29/31

Summary

A new era in SS laser technology

Light engines of the futureApproaching light-bulb efficienciesMonolithic integrated architectures

New laser sources and materialsceramic lasers

New infra-red materialsDiode pump sources in the visible and mid-IR

New laser modalitiesPhase and Spectral beam combining

Phase and mode controlmulti-pulse and multi-wavelength regimes

Many new application areasPrecision machining for electronics, medical, aeronauticsSSL enter medical therapy, imaging and surgery

Multiple applications in the defense and security fields


30/31

Investments so far in the Townes Institute

Major Investment in Optical Fibers and Fiber Fabrication

> $2M investment in fiber fabrication facilities operational 2011

3 new faculty in optical fiber design, fabrication and applications

2010- 2011 Ceramic Laser Materials Initiative

Asst. Prof. Romain Gaume from Stanford to join in

Summer 2011.

Relocation of Stanford ceramics laboratory to UCF.

Appointment of 1-2 Research professors.

Townes Institute moves into Attoscience

Prof. Zenghu Chang moved to UCF 2010 from KSU. Joint position

with Physics Department. Critical mass in femtosecond lasers, High

Harmonic Generation, EUV and attoscience

Asst Prof. Ayman

Abouraddy

Quantum Optics

Multi-functional

fibers. Mid-IR.

Prof. Axel Schulzgen

Multi-structured

fibers. Fiber lasers.

Fibers for sensing.

Multi-functional

fibers. Mid-IR.

Asst Res. Prof. Rodrigo

Amezcua-Correa

Photonic crystal fibers

High temperature silica

fibers. Fiber lasers
http://www.creol.ucf.edu/People/Details.aspx?PeopleID=10068


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Martin [email protected]

www.townes.ucf.edu

www lpl creol ucf edu
mailto:[email protected]://www.townes.ucf.edu/http://www.lpl.creol.ucf.edu/http://www.lpl.creol.ucf.edu/http://www.townes.ucf.edu/mailto:[email protected]

dr martin richardson-the future of solid state lasers

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