LiNbO 3 Crystal
LiNbO 3 is widely used as electro-optic modulator
and Q-switch for Nd:YAG, Nd:YLF and Ti:Sapphire lasers as well as
modulator for fiber optics, etc. The transverse modulation is mostly
employed for LiNbO 3 crystal.
If the light propagates in z-axis and electric field
applies to x-axis, the refractive retardation will be G = p Lnr22V/
l d. The electro-optic coefficients of LiNbO 3 are:
r 33 = 32 pm/V, r 31 = 10 pm/V, r 22 = 6.8 pm/V at low frequency
r 33 = 31 pm/V, r 31 = 8.6 pm/V, r 22 = 3.4 pm/V at high electric
frequency.
MgO:LiNbO 3 and ZnO: LiNbO 3 crystals have similar
electro-optic properties to LiNbO 3 but with higher damage threshold.
The refractive index of an optical medium is altered
by the presence of sound, this is called acousto-optic effect which
can be used in many devices include optical modulators, switches,
deflectors, filters, frequency shifters and spectrum analyzers. Dayoptics
provide several kinds of acousto-optic crystals: LiNbO 3 SAW wafers,
LiTaO 3 SAW wafers. TeO 2 and PbMnO 4 crystals.
KTP Crystal
KTP has promising E-O and dielectric properties comparable
to those of LiNbO 3 , which makes it extremely useful to various E-O
devices. The following table gives the comparison of KTP and thos
commonly used E-O modulator materials:
| Material |
Phase |
Amplitude |
| e |
5 |
r pm/V |
k 10 -6 /°C |
n 7 r 2 / e
(pm/V) 2 |
r pm/V |
k 10 -6 /°C |
n 7 r 2 / e
(pm/V) 2 |
| KTP |
15.4 |
1.80 |
35.0 |
31 |
6130 |
27.0 |
11.7 |
3650 |
| LiNbO 3 |
27.9 |
2.20 |
31.0 |
82 |
7410 |
20.1 |
42 |
3500 |
| KD*P |
48.0 |
1.47 |
26.4 |
9 |
178 |
24.0 |
8 |
178 |
| LiIO 3 |
5.9 |
1.47 |
6.4 |
24 |
335 |
1.2 |
15 |
124 |
When these properties are combined with high damage
threshold, low optical loss at high average power, wide optical bandwidth,
thermal and mechanical stability, KTP crystals are expected to replace
LiNbO 3 crystals as E-O modulators, especially for mode-locking diode
laser pumped Nd:YAG and Nd:YLF lasers as well as Ti:Sapphire and Cr:LiSrAlF
6 lasers.
LiTaO 3
LiTaO 3 crystal is also widely used E-O crystal, due
to its optical, NLO and E-O poperties similar to those of LiNbO 3
crystal, but with higher damage threshold (> 500 MW/cm 2 for ns pulsed).
Properties
Transparent Range: 0.4 - 5.0 µm;
E-O Coefficient: r 33 =30.4;
Refractive Indices: n o =2.176, n e =2.180 @ 633 nm.
Capabilities:
Diameter: f 40mm ~ f 102mm
Length: 50mm ~ 150mm
Orientation: X, Z, 36°Y, 42°Y, 128°Y
Polish: 0.016 m m
Wafers:
- Diameter: f 40mm ~ f 102mm
- Length: 0.2~1.2mm
- Orientation: X, Z, 36°Y, 42°Y, 128°Y
- Flatness:
<10mm for f 40 ~ 65mm
<15mm for f 65 ~ 102mm
- Bow:
<20mm for f 40~ 65 mm
<40mm for f 65 ~102mm
Slices:
- Size: 100x45x1.5mm ~ 120x40x2mm
Parameter of LN and LT
Part Name: ------------LiNbo3 ------------LiTaO3
Crystal Class: -------Trigonal -------------Trigonal
Point Group:---------------3m------------------- 3m
Space Group: --------------R3c ----------------R3c
Lattice Point: ----a:0.5148 c:1.3863 --------a:0.5154c:1.3784
Melting Point: -----------1250 ---------------------1650
Density: -------------------4.64 ---------------------7.46
Curie Temp: ---------------~1160 --------------------~607
Hardness:---------------------5-------------------------- 5.5
Dielectric Coefficient; -e 11/E0:85 e 33/E0:29.5--------- e 11/E0:51.7
e33/E0:44.5
Elastic Stiffness ----------CE11:2.04 ---------------CE11:2.33
Coefficient:(x10 -11 C/m2) -------CE11:2.46 -------CE11:2.77
Piezoelectric Stresses --------d22:2.04 -------------d22:2.4
Coefficient (x10 -11 C/N) --------d22:19.22 -----------------d22:0.8
BBO Crystal
BBO crystals with Z-cut is an excellent electro-optic
crystal combining good physical properties, it's suitable for high
power applications. It launchs a super Q-switch for a cw diode pumped
Nd:YAG laser with average power >50w.Please refer to Page 14 for
more information about BBO crystal.
We can provide as large as 10x10x25mm BBO for
high power application.
