Electro-optic polymers for wideband THz-applications
1
Electro-optic polymers for wideband THz-applications Alexander Sinyukov, Peter Lindahl, Joey French, and L. Michael Hayden, Department of Physics, University of Maryland, Baltimore County, Baltimore, MD 21250 Meng He and Robert J. Twieg, Department of Chemistry, Kent State University, Kent, OH 44242 Materials Optical rectification Electro-optic detection Electro-optic polymer composites are fabricated from mixtures of nonlinear optical chromophore guests and polymer hosts (PMMA, APC). χ (2) ≠0 P NL (Ω )= χ (2) (Ω; ω ,Ω− ω ) E ( ω ) E ( ω ) E THz ( t ,Ω )~ ∂ 2 P NL ( t) ∂ t 2 E opt ( t,Δ ω ) Wideband, sub-ps visible light generates far-IR femtosecond pulses via three wave mixing amongst the input frequencies. THz beam pellicle polarizer polarizer compensator (2) material polymer [110] ZnTe [1-10] The THz beam provides the electric field which modulates the index of refraction in the (2) material. Balanced detection increases the signal-to-noise ratio. ΔΓ polymer = 2 πn 2 lr 33 sin 2 θ 3 λ n 2 − sin 2 θ E THz ΔΓ ZnTe = πn 3 lr 41 λ E THz Experimental setup EO polymer properties •high electro-optic coefficient (r 33 = 50 pm/V @ 785 nm) no phonon absorption !! phase matching ?? n = 1.75 @ 800 nm, static dielectric constant, ~ 3 50-500 m thick versatility • cheap ! N N N Lemke-e =8.31 Debye, =12165 esu Predicted frequency response l c = π Δ k = πc ω THz n opt − λ opt dn opt dλ λ opt − n THz f (Ω)= C opt (Ω) χ eff (2) (Ω; ω 0 , ω 0 −Ω) e i Δ k + ( ω 0 ,Ω) −1 i Δ k + ( ω 0 ,Ω) ⎡ ⎣ ⎢ ⎢ ⎤ ⎦ ⎥ ⎥ 13 m thick scaling phonon absorption gaps in ZnTe, GaP response very thin crystals required for wideband response no resonances in polymer composites coherence length tuning possible in polymers polymers have larger response (r polymer > r crystal ) film ITO glass 1 cm THz-performance of EO polymer Wideband emission CDHF-MOE-V = 12.3 Debye, = 18576 esu. /M = 1.9 x Lemke DCDHF-6-V = 12.7 Debye, = 18640 esu /M = 1.7 x Lemke Laser 180 fs, 795 nm, 250 KHz, 1 W Teflon (blocks 800 nm, passes THz beam) Pellic Balanced d Off-axis paraboloid EO sensor EO emitter λ/4-p Variaλ dλay stag Lok-in poλarizr THz poλa N O C N C N C N O N O O C N N C C N -0.8 -0.4 0.0 0.4 4 3 2 1 0 Time delay (ps) 0.2 0.1 0.0 3 2 1 0 THz 250 ZnT snsor 147 two-λayr poλyr snsor 64 singλ-λayr poλyr snsor 100pV 80 60 40 20 0 12 10 8 6 4 2 0 THz in-phase poling out-of-phase poling 1 mm ZnTe emitter Emitter: two-layer polymer stack Sensor: 20 m ZnTe 0.01 0.1 1 10 80 60 40 20 0 THz GaP ZnTe Lemke/PMMA 1.0 0.8 0.6 0.4 0.2 0.0 120 110 100 90 80 70 60 50 40 Temperature, C 20%DCDHF-MOE-6V 20% DCDHF-6-V 60%APC T g = 101 C 40%DCDHF-6-V 60%APC T g = 97 C 40%Lemke 60%APC T g = 95 C 70 60 50 40 30 20 10 0 160 140 120 100 80 60 40 20 0 Poling field (V/µm) 40% DCDHF-6-V 60% APC 20% DCDHF-6-V 20% DCDHF-MOE-V 60% APC 40% Lemke 60% APC -0.6 -0.4 -0.2 0.0 0.2 0.4 8 7 6 5 4 3 2 1 0 Time delay (ps) 1 mm ZnTe emitter 96µm polymer emitter 2 mm ZnTe sensor
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film. ITO. 1 cm. glass. THz beam. pellicle. [110]. polymer. [1-10]. polarizer. ZnTe. c (2) material. compensator. polarizer. Electro-optic polymers for wideband THz-applications Alexander Sinyukov, Peter Lindahl, Joey French, and L. Michael Hayden , - PowerPoint PPT Presentation
Transcript of Electro-optic polymers for wideband THz-applications
Electro-optic polymers for wideband THz-applicationsAlexander Sinyukov, Peter Lindahl, Joey French, and L. Michael Hayden, Department of Physics, University of Maryland, Baltimore County, Baltimore, MD 21250Meng He and Robert J. Twieg, Department of Chemistry, Kent State University, Kent, OH 44242
Materials Optical rectification
Electro-optic detection
Electro-optic polymer composites are fabricated from mixtures of nonlinear optical chromophore guests and polymer hosts (PMMA, APC).
χ (2) ≠0
PNL(Ω) =χ (2)(Ω;ω,Ω −ω)E(ω)E(ω)
ETHz(t,Ω)~∂2P NL(t)∂t2
Eopt(t,Δω)
Wideband, sub-ps visible light generates far-IR femtosecond pulses via three wave mixing amongst the input frequencies.
THz beam
pellicle
polarizer
polarizer
compensator
(2) material
polymer[110]
ZnTe
[1-10]
The THz beam provides the electric field which modulates the index of refraction in the (2) material. Balanced detection increases the signal-to-noise ratio.
ΔΓpolymer=2πn2lr33sin2θ
3λ n2 −sin2θETHzΔΓZnTe=
πn3lr41
λETHz
Experimental setup
EO polymer properties
•high electro-optic coefficient (r33 = 50 pm/V @ 785 nm)
no phonon absorption !! phase matching ??n = 1.75 @ 800 nm,static dielectric constant, ~ 350-500 m thickversatility• cheap !
N
N
N
Lemke-e =8.31 Debye, =12165 esu
Predicted frequency response
lc =πΔk
=πc
ωTHznopt−λoptdnoptdλ λopt
−nTHz
f (Ω) =Copt(Ω)χeff(2)(Ω;ω0,ω0 −Ω)
eiΔk+(ω0,Ω) −1iΔk+(ω0,Ω)
⎡
⎣ ⎢ ⎢
⎤
⎦ ⎥ ⎥
13 m thick scaling
phonon absorption gaps in ZnTe, GaP response
very thin crystals required for wideband response
no resonances in polymer composites
coherence length tuning possible in polymers
polymers have larger response (rpolymer > rcrystal)
film
ITO
glass
1 cm
THz-performance of EO polymer
Wideband emission
DCDHF-MOE-V = 12.3 Debye, = 18576 esu.
/M = 1.9 x Lemke
DCDHF-6-V = 12.7 Debye, = 18640 esu/M = 1.7 x Lemke
Laser180 fs, 795 nm,250 KHz, 1 W
Teflon(blocks 800 nm,passes THz beam)
Pellicle
Balanced detectors
Off-axisparaboloid
EOsensorEOemitter
λ/4-plate
Variabledelay stage
-Lock in
polarizerTHz
polarizer
N
O
C
N
C
N
C
N
O
N
O
O
C
N
N
C
C
N
-0.8
-0.4
0.0
0.4
43210Time delay (ps)
0.2
0.1
0.03210 THz
250 m ZnTe sensor147 - m two layer polymer sensor64 - m single layer polymer sensor
100pV
80
60
40
20
0121086420
THz
in-phase poling out-of-phase poling 1 mm ZnTe emitter
Emitter: two-layer polymer stackSensor: 20 m ZnTe
0.01
0.1
1
10
806040200THz
GaP
ZnTe
Lemke/PMMA
1.0
0.8
0.6
0.4
0.2
0.0
120110100908070605040Temperature, C
20%DCDHF-MOE-6V 20% DCDHF-6-V 60%APC Tg = 101 C
40%DCDHF-6-V 60%APC Tg = 97 C
40%Lemke 60%APC Tg = 95 C
70
60
50
40
30
20
10
0160140120100806040200
Poling field (V/µm)
40% DCDHF-6-V 60% APC
20% DCDHF-6-V 20% DCDHF-MOE-V 60% APC
40% Lemke 60% APC
-0.6
-0.4
-0.2
0.0
0.2
0.4
876543210Time delay (ps)
1 mm ZnTe emitter 96µm polymer emitter
2 mm ZnTe sensor
