recent advances in mid-ir solid state lasers, opos and qcls · commercial products developed by...

Recent Advances in Mid-IR Solid State Lasers, OPOs and QCLs

Peter MoultonVP/CTO

Q-Peak, Inc.

Outline

• Diode-pumped mid-IR sources– Er:YLF– Tm-laser-pumped Ho:YLF

• OPOs– ZnGeP2

(ZGP) OPO pumped by Ho:YLF laser– Tandem OPO (KTA –

CdSe)• QCL-based sources

Commercial products developed by Q-Peak

Laser 1-2-3 Titan CW, P, ML

MPS Lasers (early)

MPS Gain Module

MPS LaserHead

The Laser 1-2-3 provided a range of wavelengths, into the mid-IR

Pump cavity, rod and mirrors for solid state laser

Q-Peak’s DPSSL design obtains high efficiency and high beam quality with side-pumping

Diode laser

Diode laser

Laser

crystal

Cylinder lens Laser

beam

Pump

beam

Multi-Pass Slab (MPS)US Patent 5,774,489

“Gain Module”Applied to Nd:YLF, Nd:YVO4

, Nd:YAG

Yb:S-FAP, Yb:YAG, Tm:YLF, Er:YLF, Cr:LiSAF

Er3+

Energy Level Diagram

4F7/2

4S3/2

2H11/2

4F9/2

4I9/2

4I11/2

4I13/2

4I15/2

Pump

2.8 m

W11

W11

W22

W22

N2

N1

W50

W50

Earlier end-pumped work produced cw

powers from several materials

0 500 1000 1500 2000 2500 30000

100

200

300

400

500

Diode power (mW)

Pow

er (m

W)

Er:YSGG

Er:GGG

Er:BYF

Er:YAG

Previous results –

Diode-pumped Er:YLF-lasers

• Maximum slope efficiency :– ~ 40% -

Ti:Sapphire excitation (970 nm, longitudinal)M.Pollnau

et al., “Efficiency of Erbium 3-m crystal and fiber lasers”

IEEE J. of Quantum Electronics, 32, 657-663 (1996)– ~ 35% -

Diode-Pumped (970 nm, longitudinal) T. Jensen, A. Diening, G. Huber, and B.H.T. Chai, “Investigation

of diode-pumped 2.8-m Er:LiYF4 lasers with various doping levels, Opt. Lett., 21, 585-587 (1996).

• Maximum CW output:– ~ 1.1 W Diode-pumped (970 nm, longitudinal, fiber-coupled diode

laser)T. Jensen et al. (see above)

• Drawbacks:• difficult to scale to higher powers• fracture of the laser elements at 4-6 W pump power (0.3-0.5 mm

spot)

Absorption Properties of Er:YLF

Laser Crystals

Polarized absorption spectra for 15% Er:YLF

crystal at 300 K.

0

5

10

15

20

25

30

960 965 970 975 980 985 990

Wavelength, nm

Abs

orpt

ion

coef

ficie

nt, c

m-1

0

5

10

15

20

25

30

PiSigma

Brewster-angle design for side-pumped Er:YLF

laser

Er:YLF

Active Element:Brewster/Brewster-cut slab: 28-mm longClear aperture 1.25 x 6 mm.

Experimental Set-Up

DL

15% Er:YLF DL

HR r=10 cmcc

HR

OC r=10 cmcc

HR

a) Compact 3-pass resonator

DL

15% Er:YLF DL

HR r=30 cmcc

HR

OC r=10 cmcc

HR

BRF

b) “Long” resonator

Rate equations:dN2 /dt = W + W11 (N1 )2 – W22 (N2 )2 – N2 /2 ,

dN1 /dt = 21 N2 /2 + W22 (N2 )2 - 2 W11 (N1 )2 – N1 /1 ,

The net gain coefficient:g =

(b2 N2 –b1 N1 ),

Definitions:W11 , W22 - up-conversion rate parameters,

1 and 2 - lifetimes for spontaneous decay and

21 - the branching ratio.

- spectroscopic cross section for the transition and

b1 , b2 - Boltzmann factors for the lower and upper manifolds.

1 10 msec

2 4.0 msec

W11 3x10-17

cm3/sec

W22 1.8x10-17

cm3/sec

21 0.39

3x10-20

cm2

b1 0.113

b2 0.2

Theoretical Model

Table. Values for 15% Er:YLF used in the calculations (Based on the data from: M.Pollnau et al. IEEE J. QE, 321, 657-663 (1996)).

Gain Calculation

0.01

0.1

1

1.00E+21 1.00E+22 1.00E+23

Pump Rate, cm-3

Gai

n co

effc

ient

, cm

-1Linear

Square root

Calculation

20-W pump

Experiment

10-W

Er:YLF

CW Laser Operation

Three-Pass Geometry

~ 40 cm~ 20 cmResonator lengthT ~ 4% at 2600-2900 nmT ~ 4% at ~ 2600-2900 nmOutput coupling

2600-3000 nmHR mirrorlongshort

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0 5 10 15 20 25 30 35 40Total diode power, W

Out

put p

ower

, W

shortlong

15% slope efficiency

16.5% slope efficiency

Er:YLF

quasi-CW Laser Operation

Three-Pass Geometry

~ 40 cmResonator lengthT ~ 4% at 2600-2900 nmOutput coupling

2600-3000 nmHR mirror

0

2

4

6

8

10

12

0 5 10 15 20 25 30 35 40 45 50Diode current, A

Peak

pow

er, W 25%

33%50%CW

Calculated Wavelengths for Transitions Between 4I11/2

and 4I13/2

Manifolds in Er:YLF

Manifold 4I/11/2 Level 1 2 3 4 5 Energy,

cm-1 10222 10235 10283 10289 10315

nm nm nm nm nm 7 6738 2870.3 2859.6 2820.9 2816.1 2795.6 6 6724 2858.8 2848.2 2809.8 2805.0 2784.7 5 6697 2836.9 2826.5 2788.6 2784.0 2764.0 4 6674 2818.5 2808.2 2770.9 2766.3 2746.5 3 6579 2745.0 2735.2 2699.8 2695.4 2676.7 2 6539 2715.2 2705.6 2670.9 2666.7 2648.3

4I13/2

1 6535 2712.2 2702.7 2668.1 2663.8 2645.5

Note:

Bold numbers indicate wavelengths for which lasing has been obtained in prior work.

Er:YLF

CW laser operation

wavelength tuning

Wavelength tuning of Er:YLF

laser with a 1-plate birefringent filter

0

200

400

600

800

1000

1200

1400

2700 2720 2740 2760 2780 2800 2820 2840Wavelength, nm

Out

put P

ower

, mW

Mid-IR source: Tm-doped laser-pumped, Ho:YLF laser pumped, ZGP OPO

ZGPOPO

Ho:YLFlaser

Tmlaser

100 mJ2050 nmCW

1940 nmQ-switched

2050 nm

Broadly tunablemid-IR

Why a laser pumping a laser pumping a laser?

• Semiconductor diode laser– high electrical-optical efficiency but– only cw-like output, poor beam quality at high powers

• Tm solid state laser (bulk or fiber)– good (in theory) conversion of poor quality beam from diode

lasers into diffraction-limited beam but– limitations in stored energy and nonlinear/damage issues

prevent generation of high pulse energies• Bulk solid state Ho:YLF laser

– good conversion of pump power to output power– high energy storage and extraction capability allows

generation of high-peak-power pulses

References on resonantly pumped Ho lasers

P.F. Moulton, “Industry R&D related to 2-m lidars,”

Second Review of 2-m Solid State Laser Technology, NASA Headquarters, Washington, DC, May 18-19, 1992.

R.C. Stoneman

and L. Esterowitz, Opt. Lett. 17, 736 (1992).

D.W Hart, M. Jani

and N.P. Barnes, Opt. Lett. 21, 728 (1996).

M. Petros, J. Yu, U. N. Singh and N.P. Barnes, “High energy directly pumped Ho:YLF laser,”

in Advanced Solid State Lasers, OSA Technical Digest (Optical Society of America, Washington, DC, 2000), pp. 79-81.

P.A. Budni, M.L. Lemons, J.R. Mosto, and E.P. Chicklis, IEEE J. Sel. Topics in Quantum Electron. 6, 629 (2000).

P.A. Budni, M.L. Lemons, C.A. Miller, P.A. Ketteridge, L.A. Pomeranz, T.M. Pollak, P.G. Schuneman, K.L. Lanier, J.R. Mosto, and E.P. Chicklis, “High power 1.9 micron pumped solid state holmium lasers,”

in Conference on Lasers and Electro-Optics, OSA Technical Digest (Optical Society of America, Washington, DC, 2000), p 564.

L.D. DeLoach, S.A. Payne, L.L. Chase, L.K. Smith, W.L. Kway

and W.F. Krupke, IEEE J. Quantum Electron. 29, 1179 (1993).

W.F. Krupke

and L.L. Chase, Optical and Quantum Electron. 22, S1 (1989).

1D2

3F2

1G4

3F33H4

3H5 3F4

3H6

Pump~790 nm 1.9 m

N1

N0

Cross-relaxation

Lasing

N3~14 ms

~1 ms

(1%)

•1 2 pump process due to cross-relaxation•low up-conversion•low heat generation (~20 %)

Tm3+

Energy Level Diagram

Emission Cross-Section –

3.5% Tm:YLF

0.0E+00

5.0E-22

1.0E-21

1.5E-21

2.0E-21

2.5E-21

3.0E-21

3.5E-21

4.0E-21

4.5E-21

5.0E-21

1600 1650 1700 1750 1800 1850 1900 1950 2000

Wavelength, nm

Cro

ss s

ectio

n, c

m 2

Polarized emission cross-section 3F4 3H6 for Tm:YLF (calculated from absorption spectra).

Gain Calculation –

3.5% Tm:YLF

-0.25

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

1800 1825 1850 1875 1900 1925 1950 1975 2000

Wavelength, nm

Gai

n co

effic

ient

, cm

-1

Inversion fraction

Polarized gain in Tm:YLF at two values of inversion fractiong() = N [ pem () - (1-p)abs () ],where p – inversion fraction, N - Tm-concentration

Tunable power from Tm:YLF laser

0

1

2

3

4

5

6

1900 1920 1940 1960 1980 2000 2020 2040 2060 2080

Wavelength, nm

Out

put p

ower

, W

T=3 %T=13%

Tm:YLF Active Element:Rectangular slab: 22-mm longClear aperture 2x6 mm.

Experimental Set-Up –

Tm:YLF Laser

Tm:YLF DL

HR

OC

DL

BRF

Tm:YLF DL

DL

Tm:YLF –

Dual GM Oscillator –

3 passes

0

5

10

15

20

25

30

0 20 40 60 80 100 120 140 160 180

Diode pump power, W

Out

put p

ower

, W


Ho:YLF vs. Ho:YAG

• Why Ho:YLF (Q-Peak, NASA) ?– Long upper laser level lifetime ~ 15 ms (in theory)– Highest emission cross-section known for Ho-doped crystals

= 1.84 x 10-20

cm2

– Esat

= 5.3 J/cm2

– Naturally birefringent material– Low dn/dT

–> weak thermal lensing– ~5% quantum defect

• Compared to Ho:YAG (BAE, SORC)– Upper state lifetime 7 ms– Emission cross section 0.98 x 10-20

cm2

– Esat

= 9.6 J/cm2

– 10% quantum defect– Isotropic, higher thermal lensing, stress birefringence– Superior thermo-mechanical properties

Pumping Ho:YLF with Tm:YLF laser

0

0.5

1

1.5

2

2.5

3

3.5

1800 1850 1900 1950 2000 2050 2100 2150

Wavelength, nm

Abs

orpt

ion

coef

ficie

nt, c

m-1

Ho abs - PiTm-tuning

2.0% Ho:YLF

Ho:YLF gain is predicted to be high for a 59% inversion fraction

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

1800 1850 1900 1950 2000 2050 2100 2150

Wavelength, nm

Gai

n, c

m-1

0.590.2

Schematic layout of the end-pumped Ho:YLF laser

HR

OC

AOM

Ho:YLF

Tm:YLF laser #1

Tm:YLF laser #2

DM

DM

DM –

Dichroic

Mirror, AOM –

Acousto-Optic Modulator, OC –

Output Coupler, HR –

High Reflector

CW Ho:YLF Laser Operation (TEMoo

)

0

5

10

15

20

25

0 10 20 30 40 50 60

Total Tm pump power, W

Ho:

YLF

CW

out

put,

W

10%15%40%70%



Toc

Ho:YLF laser operation is in TEMoo

mode

Ho:YLF –

Q-Switched Operation (TEMoo)

0

2

4

6

8

10

12

14

16

18

0 500 1000 1500 2000 2500

Repetition rate, Hz

Out

put p

ower

, W

0

5

10

15

20

25

30

35

40

Puls

e en

ergy

, mJ

PE

Ho:YLF –

Pulsewidth vs

repetition rate

0

5

10

15

20

25

0 200 400 600 800 1000 1200

Repetition rate, Hz

Puls

ewid

th, n

s

Ho-laser Power Scaling

• CW Tm:fiber lasers with output >100 W emerge as alternative to bulk Tm-laser:

– Turn key operation– Cost-effective– Maintenance-free– Fiber delivery (no surprise!)

Operation regime CW

Operational temperature RT

Output power ≥

100 W

Lasing wavelength range: 1750-2200 nm

Polarization: Random

Linewidth ≤

2 nm

Tm-fiber laser TLR-100-1940 (IPG Photonics, www.ipgphotonics.com

)

Schematic layout of the fiber-pumped Ho:YLF laser shows two-crystal design

HR

OC AOM Ho:YLF

Tm:fiber laser

DMDM

Ho:YLF

PBS

/2

DM DM

DM – Dichroic Mirror, AOM – Acousto-Optic Modulator, OC – Output Coupler, HR – High Reflector

CW laser operation provides 40-W of output power

0

5

10

15

20

25

30

35

40

45

50

0 20 40 60 80 100 120

Total Tm-pump power, W

Ho:

YLF

outp

ut, W

40%70%

Slope Efficiency 42%Quantum efficiency 74% (absorbed)

Output transmission

Ho:YLF Q-switched laser operation observed at pulse rates from 200-1000 Hz

0

5

10

15

20

25

30

35

40

45

50

0 20 40 60 80 100 120

Total Tm-pump power, W

Ho:

YLF

puls

e en

ergy

, mJ

w1-1kw1-400w1-200w2-200w2-400

"Moderate" focusing

"Loose" focusing

28 ns

20 ns

17 ns

32 ns

22 ns

We chicken out

Ho:YLF effective storage time is around 2 msec

based on energy vs. pulse rate data

0

5

10

15

20

25

30

35

40

0 2 4 6 8 10 12 14 16 18 20

Period (msec)

Puls

e en

ergy

(mJ)

Data

Theory, 1.89 msec

Reasons: Bleaching, upconversion?

Theoretical tuning curve for

Ho:YLF-pumped ZGP OPO

2

3

4

5

6

7

8

9

51 52 53 54 55 56 57 58

Angle (degrees)

Sign

al, i

dler

wav

elen

gths

(um

)

ZGP OPO -

Layout

• ZGP OPO:– ZGP 1 cm-long– Type I, 53o-cut – Flat/flat resonator– Singly resonant cavity– Pump –

double pass– ~6 cm-long resonator– OC 38% at 3.2 um

R=38% 3.2 um

HR 2.05 um

HT 5.7 um

HR 3.2 um

HT 2.05 and 5.7 um

ZGP

ZGP OPO operation –

pulse energy at 3200 nm

0

2

4

6

8

10

12

14

0 5 10 15 20 25 30

Pump pulse energy, mJ

OPO

pul

se e

nerg

y, m

J

50 Hz200 Hz400 Hz

Slope efficiency:50 Hz 60%200 Hz 56%400 Hz 63%

Packaged Tm:YLF, Ho:YLF, ZGP OPO system

Conclusions

• Fiber-laser pumped Ho:YLF crystal (and similar materials) combines best features of fiber and bulk solid state lasers

– High beam quality and efficiency of fiber lasers– Energy storage capability of bulk lasers

• Recent advances in commercial (IPG) Tm:fiber lasers have made 100-W devices available. Future powers even higher?

• Ho:YLF laser has a favorable combination of energy storage and high gain cross section, suitable for high-energy, short-pulse

Q-switched oscillators and amplifiers at 2050 nm

• 2050-nm wavelength is eyesafe, transmits well through the atmosphere and is a good pump wavelength for ZGP OPOs

providing coverage of entire mid-IR wavelength region

• Scaling to 40 W average power, 45 mJ

pulses at 20 ns to date• Stayed tuned, another 200 W of pump power yet to go!

Early Nd:YLF

MOPA system generated

40 W Q-switched at 5 kHz

EOQ-switch

Two-module Nd:YLF Oscillator1st StageAmplifier

2nd StageAmplifier

50 W CW40 W Q-Sw

@ 5 kHz14-ns pulsewidth

Cylinderlens

Cylinderlens

Two-Gain-Module oscillator generated 14-ns pulses at a 5-kHz pulse rate

10 ns per division

Data on IR OPOs pumped by MPS system

• Pump source: 40 W, 5 kHz, 15 ns Nd:YLF

MOPA• KTA OPO

– 60-mm crystal length, 80-degree cut• 30 W pump, 5 kHz PRR• 10 W at 1530 nm, 3 W at 3340 nm

– 40-mm crystal length, 60-degree cut• 31 W pump, 5 kHz PRR• 2.5-5 W of idler tunable from 2100-3100 nm

• PPLN OPO– 19-mm crystal length, 30.8-um pitch

• 30 W pump, 5 kHz PRR• 5.2 W at 2610-nm idler, 3W at 1720-nm signal

Plot of KTP and KTA IR transmission

3000 3200 3400 3600 3800 40000

20

40

60

80

100T = 75% @ 3297nm

T = 23% @ 3297nm

KTA 2cm KTP 2cm

Wavelength (nm)

%T

Tuning curve for MPS-driven KTA OPO

0

1

2

3

4

5

6

2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3 3.1 3.2

Wavelength (um)

Pow

er (W

)

Design for high-power KTA OPO

Moderate threshold Moderate efficiency High damage Low feedback

signal out

pump in

pump& idler out

CaF2prism

KTA x-cut

Four KTA Crystals 1 x 1 x 2 cm each

Highest-average-power OPO uses KTA

0 20 40 60 80 100 1200

5

10

15

20

25

30

35

Pump Power (Watts)

Sign

al P

ower

(Wat

ts)

M.S. Webb et al. Opt.Lett. 23, 1161 (1998)

High-average-power, 100-Hz OPO used KTA

0 20 40 60 80 100 1200

5

10

15

20

25

30

35

Pump Power (Watts)

Sign

al P

ower

(Wat

ts)

M.S. Webb et al. Opt. Lett. 23, 1161 (1998)

M2

= 30 M2

= 41

Results with two different pump lasers, pump laser pulsewidths

22.5 and 17.5 ns

Tandem OPO for infrared DIAL

Tandem OPO scheme

Nd-doped,Q-switched laser KTA OPO CdSe OPO

IR seed source

IR seed source

Nd-dopedseed laser

1.5 - 3.6 m

3.3 - 11 m

Or: PPLN,

other KTP isomorphs

Or: AgGaSe2

ZnGeP2

Angle-tuned Pump-tuned, NCPM

Tandem OPO tuning with x-

and y-cut KTA

1

2

3

4

5

6

7

8

9

10

11

12

45 50 55 60 65 70 75 80 85 90

KTA Phasematch angle (degrees)

Wav

elen

gth

(um

)

y-cut KTA

x-cut KTACdSe signal and idler

KTA signal and idler

Angle-tuning data on KTA OPO

1.2

1.4

1.6

1.8

2.0

2.2

2.4

2.6

2.8

3.0

3.2

3.4

3.6

3.8

45 50 55 60 65 70 75 80 85 90

Angle (degrees)

Wav

elen

gth

(um

)

y-cut idler data

x-cut idler data

x-cut signal data

y-cut signal data

Seeded Nd:YLF ring pump laser (lamp pumped(

HR Seed laser

Optical isolator

PD

LockingElectronics

PZT

OC

HR

HR

Dove prism

Pockels

cell

/2

Nd:YLF rod

60 mJ

@ 1053 nm

Polarizer

Aperture

Tandem OPO demonstration

Nd:YLF pump laser

CdSe

KTA

CdSe OPO idler8.3-10.6 um

3-4.5 mJ

KTA OPO idler3.0-3.45 um

CdSe OPO signal

KTA OPO idler

EOSI 2010 ExternalCavity Diode Laser

1530-1560 nm

Seed laser

Optical isolator

>200 mJ, 20 Hz

40-50 mJ

signal25 mJ

idler

KTA OPO pumping: seeded and unseeded laser

0

10

20

30

40

50

60

70

0 50 100 150 200 250Pump energy, mJ

KTA

OPO

tota

l out

put e

nerg

y, m

J

Seeded pump

Unseeded pump

I/O data for x-

and y-cut KTA

0

10

20

30

40

50

60

0 50 100 150 200 250Pump energy (mJ)

OPO

out

put e

nerg

y (m

J)

y-cut NCPM signal

y-cut NCPM idler

x-cut 66 deg. signal

x-cut 66 deg. idler

KTA OPO pump and signal pulse profiles

Seeded pump Unseeded pump

1 - pump pulse2 - signal pulse

CdSe OPO I/O data

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0 5 10 15 20 25 30

Pump energy (mJ)

Tota

l OPO

ene

rgy

(mJ)

3.45 um pump

3.18 um pump

CdSe

OPO pump and signal pulse profiles

Diode-pumped, 1-kHz Nd:YLF

OPO pump-system layout

L1 & L4, collimating lenses,L2 & L3, relay-imaging lenses

QCW-end-pumped, AO Q-switched, Nd:YLF

Oscillator

1st StageAmplifier

2nd StageAmplifier

Isolator /2plate L1

L4

L2L3OPO pump beam

Nd:YLF

pump generates 18 mJ/pulse at 1 kHz, with 10-nsec-duration pulses, TEMoo

output

0

5

10

15

20

25

20 40 60 80 100 120 140

Total amplifier pump power (W)

Out

put p

ulse

ene

rgy

(mJ)

0.9 mJ1.9 mJ2.8 mJ3.6 mJ4.7 mJ

KTA OPO performance

(signal 1.504 m, idler 3.45 m)

y = 0.4738x - 0.9086

0

1

2

3

4

5

6

7

8

0 5 10 15 20

Pump energy (mJ)

KTA

OPO

out

put e

nerg

y (m

J) Total

Signal

Idler

CdSe

OPO performance

(signal 5 m, idler 10.5 m)

0

50

100

150

200

250

300

350

0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5

KTA OPO idler pulse energy (mJ)

CdS

eO

PO to

tal p

ulse

ene

rgy

(J)

Overall design of rapidly tunable,

1-kHz PRR Tandem OPO

Legend:Laser diode currentMPL control (current settings, burst mode)AOBD control (RF, burst mode)Rotation control (angle)Trigger pulseBurst pulse

AOBD

MPL RF Synthesizer(rapid tuning)

Rotation control(slow tuning)

OSC AMP 3AMP 2

PC 2

Mid IR output

Rotary stages

External burst

PC 1

AMP 1

Legend:Laser diode currentMPL control (current settings, burst mode)AOBD control (RF, burst mode)Rotation control (angle)Trigger pulseBurst pulse

AOBD

MPL RF Synthesizer(rapid tuning)

Rotation control(slow tuning)

OSC AMP 3AMP 2

PC 2

Mid IR output

Rotary stages

External burst

PC 1

AMP 1

QCL-based systems

PSI (parent company of Q-Peak) now adding QCLs

into gas sensing systems

• Direct current injection devices from 0.43 2.0 m; 3.3 105 m• Frequency converted devices from 0.22 0.43 m (SHG); 2.3

4.5 m (DFG, OPO)

0.1 1.00.5 10.05.0

InGaAsAIGaAs

InGaAIPGaN

Type II IC

Type I QC

InGaAs

E-3757a

Wavelength (m)

SHG Si-Fiber Optic Win

dowPPLN-basedDFG, OPO

NO, OH

NO2O2

H2OCOOH NO

CO2

CONOCH4

NO

SO2

Ro. Vibronic Vibration Overtones FundamentalVibrational Modes

10-24

10-22

10-20

10-18

Abs

o rpt

ion

Str e

ngth

(cm

/Mo l

e cul

e,Lo

gSc

ale)

Typical Type I QCL Temperature/Current Tuning

• 7.16 micron DFB from Alpes

Lasers• 4 cm-1

total tuning range with TE cooler• 1 cm-1

high-speed current tuning range at fixed T

TE-Cooled QCL Mount

• Integral current pulser – 3 ns pulsewidth, 3 MHz rep rate• Typical average power ~ 1 mW

• Dual-Stage TE-cooler for 270 – 320 K operation

3.35 m ICL Laser

Manufactured by Maxion Technology

Singlemode

over full current tuning range >19 dB SMSR

>5 mW output power

0 5 10 15 205.0

5.5

6.0

6.5

7.0

7.5

cw - pin #3T = 80 K521 nm grating

M115C ; epi-up DFB ICL8.5-µm x 1.013-mm mesa

Volta

ge(V

)

Current (mA)

0

1

2

3

4

5

6

Pow

er(m

W/f

acet

)

3.30 3.33 3.36 3.39 3.42 3.45 3.481x10-3

0.01

0.1

1

10

100

cwT = 120KI = 11.51mA

~ 19.2 dB

= 3.3564-µm

M115C ; Epi-Up DFB ICL8.5-µm x 1.013-mm mesa

Inte

nsity

(arb

)Wavelength (µm) G-5705

DFB IC Laser Characterization

Injection Current Tuning

• Compared to simulated ethane absorption spectrum• FTIR-limited laser bandwidth

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980Wavenumber (cm

Rel

ativ

eSi

gnal

(a.u

.)

75

80

85

90

95

100

Tran

smis

sion

(%)

32mA28mA20mA22mA16mA12mAC2H6 (100ppm-m)

T= 121.8K @ 22mA

G-5708

• ~ 1.5 cm-1

current tuning range at fixed T

Quantum-cascade-laser (QCL) seeded OPO

for atmospheric sensing (NASA-funded)

MIROPO

QCLseeder

2.05-umpump laser

2.2 to 4.0 umsignal output

4.0 to 22 umidler output

Design goal:200 mJ/pulse>50-Hz PRRpump laser

Photograph of ring-cavityZGP OPO

Seed laser is 4.6-m, cw

QCL

Seed laser can be current-tuned

Summary

recent advances in mid-ir solid state lasers, opos and qcls · commercial products developed by...

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