Beta Barium Borate (BBO)

Beta Barium Borate
(BBO) Single Crystal
Introduction...
Beta-barium borate (BBO) has the following
exceptional properties that make it a very important
nonlinear crystal:
• Broad phasematching range from
410 nm to 2100 nm
• Useful optical transmission from
200 nm to 2100 nm
• Large effective nonlinear coefficients
• High laser damage threshold
• Low thermo-optic coefficient
BBO is of particular importance in the visible and far
UV. A wide variety of phasematching applications are
possible, including the following:
• Second harmonic generation to generate
wavelengths as short as 204.8 nm [8,9]
transmission
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
Optical Transmission of 8 mm Thick BBO BBO
Uncoated & Protectively Coated Coated Crystals Crystals
• Shorter wavelengths can be generated
by sum frequency mixing [7,10]
• Fifth harmonic generation of
Nd:YAG [11,12] by mixing the
fundamental and the fourth harmonic
• UV generation over a broad wavelength
range by mixing the output of a
Ti:sapphire laser.
• Many optical parametric oscillators
(OPOs) have been demonstrated for
producing wavelengths in the visible,
[14,18] near infrared, [19-21] and
the ultraviolet [22]
Transverse field Pockel cells made from BBO are useful
when high average powers or short wavelengths are
used, [30] even though the electro-optic coefficients are
relatively small (r 22 ≈(1/10)r 63 of KD*P).
0.00
0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20 2.40 2.60 2.80 3.00
wavelength -- - microns
The higher transmission trace results from a BBO crystal coated with our standard coating that minimizes reflection at 600 nm on
the input face and at 270 nm on the output face.

Optical and Electro-Optical Properties
Sellmeier Equation Contants (λ in microns @ 20°C)
n = [A + B / (1-C/l2 ) + D / (1 - E/l 2 )] 1/2
o-ray [32] e-ray [32]
A 1.7018379 1.5920433
B 1.0357554 0.7816893
C 0.018003440 0.016067891
D 1.2479989 0.8403893
E 91 91
Temperature Variation of Refractive Index [2,32]
dn o /dT = -16.6•10 -6 /°C @ 1.064 µm
dn e /dT = -9.3•10 -6 /°C @ 1.064 µm
n r = n 20 + (T - 20°C) dn/dT)
dn/dT = (GR + HR 2 ) / (2n)
o-ray [32] e-ray [32]
G -19.3007 x 10 -6 141.421 x 10 -6
H -34.9683 x 10 -6 110.8630 x 10 -6
R λ 2 / [λ 2 − (0.0652) 2 ] λ 2 / [λ 2 − (0.0730) 2 ]
Nonlinear Optical Coefficients [1,2,4] d 22 = 2.2 pm/V
d 32 > -(0.07 ± 0.03) x d 22
d 33 ≈ 0 pm/V
Electro-Optic Coefficients [5,6] r 22 s = 2.1 pm/V
r 22 T = 2.5 pm/V
r c s = 0.11 pm/V
r c T = 0.17 pm/V
Damage Threshold [2] 13.5 J/cm 2 @ 1 nsec
Acceptance Angle, Wavelength Acceptance and Walk Off
Wavelength nm Δθ(mrad-cm) Δλ(nm-cm) Walk-off Angle (°)
1064 + 1064 = 532 0.51 2.11 3.2
532 + 532 = 266 0.17 0.07 4.8
1064 + 266 = 213 0.11 0.08 5.3
488 + 488 = 244 0.16 0.05 4.7
2

Physical and Thermal Properties
Chemical Formula
Crystal Symmetry and Class
β−ΒaB204 trigonal, R3c
Optical Summetry [2] uniaxial negative
Point Group [2] 3m
Lattice Constants [2] a = 12.547(6) Å
c = 12.736(9) Å
Density 3.85 g/cm3 Melting Point 1095°C
Moh’s Hardness 4.5
Fracture Toughness [2] 150 kPa/m2 Dielectric Constants [2] Loss Tangent
K11 = 6.7
K33 = 8.1
[2] Tan δ < 0.001
Phase Transition (α-BBO stable above) 925°C
Thermal Conductivity [2]
⊥ c 0.08 W/mK
⏐⏐ c 0.8 W/mK
Specific Heat 1.91 J/cm3K Thermal Expansion [2,3] α11 = 4•10-6 /K
α33 = 36•10-6 /K
Harmonic Generation
Output Wavelength -- microns
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
THG
4HG
5HG
Type I Mixing
Type I Mixing
1+1,
1 +
1+2,
1, 1
1+3,
+ 2,
and
1 + 3
1+4
and 1 + 4
SHG
0 10 20 30 40 50 60 70 80 90
BBO BBO Phasematch Angle Angle -- - degrees degrees
3

Fundamental Wavelength -- microns
Fundamental Wavelength -- microns
Fundamental Wavelength -- microns
Sum Frequency Mixing Schemes OPO/OPA Phase Matching Curves
2.00
1.80
1.60
1.40
1.20
1.00
0.80
0.60
0.40
Type I SFM with 1.064 microns
0.20
0.168
0 10 20 30 40 50 60 70 80 90
2.00
1.80
1.60
1.40
1.20
1.00
0.80
0.60
0.40
BBO Phasematch Angle -- degrees
Type I SFM with 0.532 microns
0.706
0.646
0.587
0.527
0.467
0.407
0.347
0.288
0.228
0.20
0.195
0 10 20 30 40 50 60 70 80 90
2.00
1.80
1.60
1.40
1.20
1.00
0.80
0.60
Genertaed Wavelength -- microns
BBO Phasematch Angle -- degrees
Signal and Idler Wavelengths -- microns
75
70
65
60
55
50
45
40
35
30
25
266 nm
213 nm
355 nm
Type I OPO with Various Pumps
Type I SFM with 1.064 microns Type I OPO with Various Pumps
BBO Phasematch Angle - degrees
Type I SFM with 0.532 microns
BBO Phasematch Angle - degrees
BBO Phasematch Angle -- degrees
Type I SFM with 0.355 microns
Type I SFM with 0.355 microns
0.420
0.395
0.370
0.345
0.320
0.295
0.270
0.245
0.220
0.40
0.200
0 10 20 30 40 50 60 70 80 90
BBO Phasematch Angle - degrees
BBO Phasematch Angle -- degrees
0.304
0.291
0.278
0.265
0.252
0.239
0.226
0.213
Generated Wavelength -- microns
Generated Wavelength -- microns
4
Signal & Idler Wavelengths -- microns
532 nm
20
0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.20
Signal & and Idler Wavelengths -- microns - microns
2.30
2.20
2.10
2.00
1.90
1.80
1.70
1.60
1.50
1.40
1.30
Type II OPA with 800 nm Pump
perpendicular to pump
parallel to pump
1.20
25 26 27 28 29 30 31 32 33 34 35 36
2.20
2.00
1.80
1.60
1.40
1.20
1.00
0.80
0.60
Type I
Type II OPA with 800 nm Pump
BBO Phasematch Angle - degrees
BBO Phasematch Angle -- degrees
Type I and & Type II II Tuning Curves Curves
For OPO / OPA with 400 nm Pump
For OPO/OPA With 400 nm Pump
Type II o-ray
Type II e-ray
0.40
20 30 40 50 60 70
BBO Phasematch Angle - degrees
BBO Phasematch Angle -- degrees

BBO Single Crystals
INRAD can fabricate and polish almost any size crystal
and any orientation of BBO. In order to simplify manufacturing,
stocking and ordering, a number of standard
sizes and orientations have been defined. If the size and
orientation that you desire is not listed below, please
Contact INRAD.
Different orientations, crystallographically speaking,
refer to the angles between the beam propagation direction
and the crystallographic direction of the optic axis.
Size (mm)
5 x 5 x 0.1
5 x 5 0.25
5 x 5 x 0.5
5 x 5 x 1.0
5 x 5 x 2.0
5 x 5 x 5
5 x 5 x 10
5 x 7 x 6
5 x 7 x 8
8 x 8 x 5
8 x 8 x 10
8 x 10 x 6.5
8 x 10 x 12
10 x 12 x 6.5
10 x 12 x 8
BBO Single Crystals
Corresponding INRAD Cells
530-041, 535-040
530-041, 535-040
530-041, 535-040
530-041, 535-040
530-041, 565-110, 535-040
530-041, 534-040, 535-040, 561-044
534-040, 561-044
561-044
561-044
530-081, 534-070, 561-044
534-070, 561-044
5
All of the orientations that are listed here are Type I,
meaning that the polarization directions of the two longest
wavelengths in the mixing process are in the same direction;
the shortest wavelength in the mixing process has an
orthogonal polarization direction.
Examples of tuning applications are given for each
crystal cut; other applications are also possible.
561-044
561-044
561-044
Notes
CANNOT BE COATED
5-14B & 5-050 size
5-14B size
5-035C & 5-050 size
Autotracker size
Autotracker size
Autotracker size
Autotracker size
OPO size
Autotracker size
Autotracker size

Designation
“0”, 68.5°
“1”, 53.2°
“2”, 37.4°
“A”, 78°
“B”, 55°
“C”, 65°
“TSS”, 28.7°
“TST”, 44°
“OPO1”, 36.6°
“OPO2”, 57.5°
“M1”, 50.2°
“DGN”, 31°
“IDLR”, 20°
“OPO3”, 30°
“SHG”, 22.8°
“DGN”, 81°
“4HG”,47.6°
BBO Single Crystals
Operation
SHG
THG
SHG
THG
SHG
THG
SHG
THG
SHG
THG
SHG
THG
SHG
THG
SHG
THG
SHG
THG
SFM
SHG
THG
SFM
SFM
SHG
OPO
SHG
THG
4HG
Input Output
418-464 nm
(600-665 nm) + (300-331 nm)
454-560 nm
(651-800 nm) + (325-400 nm)
542-820 nm
(774-1165 nm) + (387-582 nm)
410-433 nm
(594-620 nm) + (297-310 nm)
448--543 nm
(642-775 nm) + (321-358 nm)
423-480 nm
(608-687 nm) + (304-343 nm)
636-1000 nm
(906-2100 nm) + (453-1050 nm)
496-675 nm
(710-960 nm) + (355-480 nm)
549-844 nm
(784-1200 nm) + (392-600 nm)
1064 + (510-567 nm)
440-525 nm
(632-750 nm) + (316-375 nm)
1064 + (243-340) nm
1064 + (510-567 nm)
1380-1460 nm
355 nm
1064 nm
1064 nm + 532 nm
532 nm
Note: An MgF 2 protective coating can be provided on all BBO crystals (except for 0.1 mm thick) for additional cost per crystal
6
209-232 nm
200-220 nm
227-280 nm
217-266 nm
271-410 nm
258-388 nm
205-216 nm
198-206 nm
224-271 nm
214-258 nm
211-240 nm
203-229 nm
318-500 nm
302-700 nm
248-337 nm
237-320 nm
275-422 nm
262-400 nm
345-370 nm
220--262 nm
211-250 nm
198-257 nm
345-370 nm
690-730 nm
410-2000 nm
532 nm
355 nm
266 nm

Ordering Information
All crystal growth, orientation, fabrication, polishing,
and testing of BBO at INRAD is done at one site, so that
you are assured of complete traceability and satisfaction
with every crystal that you purchase.
Sizes
Specify cross-section and length. Available crystal
lengths range from 50 μm, for extremely short pulse
work, up to about 15 mm for nanosecond OPO/OPA use.
Typical angular phasematching crystal lengths for frequency
mixing of nanosecond sources range from 5 mm
at the shortest wavelengths, up to 10 mm at the longest
wavelengths, with the optimum length largely being determined
by the angular acceptance of the crystal for phasematching.
Orientation
Specify Type I or Type II and the phase match angle, θ.
Crystals are oriented in a double crystal x ray spectrometer
and are typically accurate to ±5 minutes.
Type I
Finishing
Wavefront distortion in transmission is typically λ/10.
Crystals can be wedged, typically 30’ in the less critical
tuning direction or parallel to w 2 w 1 for largest w 3

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8