KTP

KTP

（Potassium Titanium Oxide Phosphate）

Applications
1.Frequency Doubling (SHG) of Nd-doped Lasers for Green / Red Output.
2.Frequency Mixing (SFM) of Nd Laser and Diode Laser for Blue Output.
3.Parametric Sources (OPG,OPA and OPO) for 0.6μm-4.5μm Tunable Output.
4.E-O Modulators , Optical Switches , Directional Couplers.
5.Optical Waveguides for Integrated NLO and E-O Devices.

Basic Properties

1.Structural and Physical Properties

2.Linear Optical Properties
·Transparency Range:
·350-4500nm,See Transparency Curve
·Refractive Indices

Therm-Optic Coefficients:
dnx/dT=1.1×10-5/℃
dnv/dT=1.3×10-5/℃
dnz/dT=1.6×10-5/℃
Sellmeier Equations:

3.NonLinear Optical Properties

Phase- Matchable Output Range: 492-1700nm

Applications for SHG and SFG of Nd:lasers
KTP is the most commonly used material for frequency doubling of Nd:YAG lasers and other Nd-doped lasers,particularly at the low or medium power density. The following Table lists the major NLO properties of KTP for frequency-doubling of Nd:YAG laser.

TO date, extra-and intra-cavity frequency doubled Nd : lasers using KTP have become a preferred green laser source for many R&D , medical , industrial and commercial applications . By using extracavity KTP SHG , over 80% conversion efficiency and 700mJ green laser were obtained with a 900 mJ injection-seeded Q-switched Nd : YAG laser.
Applied to diode-pumped Nd : laser , KTP is a basic NLO crystal for the construction of compact visible solid state laser systems . Recent advances in intracavity-doubled Nd: YVO4 and Nd:YAG lasers have increased the demand for compact green lasers used in display , construction , optical disk and laser printer. Over200mw TEM00 green outputs are available from LD pumped Nd:YVO4 and Nd:YAG lasers and 3w TEM00,mode-locked green laser was generated by intracavity SHG in a 5.3W mode -locked diode-laser pumped Nd:YAG laser. Moreover , 2.5mW green light was obtained from 50mW LD pumped and intracavity doubled Nd: YVO4 mini-lasers with a 9mm long cavity.

KTP is also a powerful crystal for SHG and SFG of laser with wavelength from about 1μm to 3.4μm . The SHG phase-matching angle and effective SHG coefficients (deff) of KTP in XY plane (0.9μm to 1.08μm) and XZ plane (1.1μm to 3.3μm) are showed as the figtures . Although KTP cut in YZ plane can be phase-matched for SHG of 1μm to3.45μm , it is seldom used in practices because of the low deff

Applications for OPG,OPA and OPO
As an efficient OPO crystal pumped by the fundamental and second harmonics of a Nd:YAG or Nd:YLF laser, KTP plays an important role in parametric sources for tunable output from visible (0.6μm)to mid-1R(4.5μm).The phase-matching angles and effective NLO coefficient for OPO/OPA pumped at 532nm and 1064nm in XZ plane are showed as following figures . NCPM KTP OPO pumped by 1064nm , the signal output is around eye safe wavelength , find applications in eye-safe devices . The OPO/OPA in XY and YZ is seldom employed because of their low effective nonlinear coefficients and other limitation.

KTP's OPO results in stable , continuous outputs of femtosecond pulse of 108Hz repetition rate and miliwatt average power levels in both signal and idler outputs . KTP ' s OPO pumped by a 1064nm Nd:laser has generated above 66% conversion efficiency for degenerate conversion from 1064 to 2120nm.

The recently developed new application is the noncritical phase-matched (NCPM)KTP OPO/OPA pumped by the tunable lasers such as Ti: Sapphire , Alexandrite and Cr:LiSrAIF6(see right figure).

The NCPM KTP OPO keeps the KTP crystal fixed in Xaxis and tunes the pumping wavelength . If a tunable Ti: Sapphire laser is used as a pumping source (0.7μm to 1μm), the output can cover the wavelength range from 1.04μm to 1.45μm (signal) and from 2.15μm to 3.2μm(idler). Due to the favorable NLO properties of NCPM KTP, as high as 45% conversion efficiency was obtained with narrow output bandwidth and good beam quality.

Quasi-Phase-Matched Waveguide
Recently , type II SHG conversion efficiency of 20%/W/cm2 was achieved by quasi-phase matched waveguide doubler , in which the phase mismatch from one section is balanced against a phase mismatch of the opposite sign from a second section . Furthermore , segmented KTP waveguides have been applied to type I quasi-phase-matchable SHG of 0.76-0.96μm for tunable Ti:Sapphire laser and directly doubled diode laser for 0.43-0.40μ output . Conversion efficiency in excess of 100%/W/ cm2 has been obtained.

Oven for heating KTP crystals:
Increasing the temperature of KTP crystal can enhance the damage threshold of KTP crystal . Therefore , for high power or high power density SHG of Nd lasers , heating KTP to a certain temperature (e.g.,80℃) is recommended . SDBRO provides precision oven with temperature controller for heating KTP . A full assembly including KTP crystal , oven and temperature controller is also available . Please refer to page xx for more information about oven & temperature controler.

Constant Crystal Optics's warranty on KTP specifications:
·Transmitting wavefront distortion: less than λ/4 @633nm
·Dimension tolerance: (W±0.1mm)×(H±0.1mm)×(L+0.2mm/-0.1)
·Clear aperture : >90% central area
·Flatness: λ/8 @633nm
·Surface quality: 10/5 Scratch/Dig
·Parallelism: better than 10 are sec.
·Perpendicularity: 15 arc min.
·Angle tolerance: Δ Θ < ±0.5° , Δ Φ < ±0.5°
·AR coating: dual wave band AR coating at 1064/532 nm for both faces
·Residual reflectivity: <0.2% at 1064 nm and <0.5% at 532 nm per surface
·Quality Warranty Period: one year under proper use

Note:
1.Constant Crystal optics has large quantities of standard size KTP crystals in-stock . The next-day delivery is available for the in-stock crystals .
The standard size crystals include 2×2×5mm,3×3×5mm and 5×5×5mm etc . with dual-band AR-coating for frequency-doubling 1064nm.
2.AR-coatings and High Reflection coatings(HR-coatings)at other wavelengths are available upon request.
3.Technical information and specific designs for KTP crystals are provided by our sales engineers and the scientists in our R&D center.