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Product Announcement

KTiOPO4 (KTP) Electro-optical Q-switch Crystal

18 Jul 2019


KTP Electro-optical Q-switch Crystal—a crystal having a high electrooptic coefficient, a low dielectric constant, and capable of operating at high frequencies

The dielectric constant ε22 of KTP varies little with frequency and is not affected by the electric coupling effect under pressure. ε33 varies greatly with frequency and is not affected by the electrical coupling effect under pressure. Especially at high frequencies, ε22 and ε33 do not vary with frequency.Outside the 500kHz-10MHz region, electro-optic devices made with KTP crystals do not produce parasitic oscillations due to piezoelectric coupling, which are severe in other electro-optic crystals. The thermal hysteresis effect of KTP is much smaller and has high temperature stability.

Nonlinear optical crystal KTiOPO4 (KTP) has excellent frequency doubling performance: large nonlinear coefficient, no delixation, optical damage threshold up to GW/cm2, and little change of phase matching condition with temperature. According to practical experience, crystals with large nonlinear coefficients often have excellent electro-optical properties. The successful development of low conductivity KTP crystal by molten salt method has greatly promoted the practical application of KTP electro-optic devices, especially in the field of high-frequency modulation.


Transparency range 350-4500 nm
Crystal structure Orthorhombic
Density 3.01 g/cm3
Mohs hardness 5
Absorption Coeffient a < 1%/cm @1064 nm and 532 nm
Refractive indices nx=1.7377, ny=1.7453, nz=1.8297 @ 1064 nm
nx=1.7780, ny=1.7886, nz=1.8887  @ 532 nm
Sellmeier equations (λ, μm) nx2=3.0065+0.03901/(λ2-0.04251)-0.01327λ2
Thermal conductivity 13 W/m/K
Therm-optic Coefficients (/℃) dnx/dT=1.1*10-5
Electro-optic coefficients Low Frequency (pm/V) High Frequency (pm/V)
r13 9.5 8.8
r23 15.7 13.8
r33 36.3 35
r51 7.3 6.9
r42 9.3 8.8
Phase Matching Range 980-3400 nm  
Flatness Less than λ/8 @ 633 nm  
Wave front distortion Less than λ/8 @ 633 nm  
Transmission surface parallelism Less than 20″  
Electrical conductivity 3.5*10-8 s/cm (c-axis,22℃,1KHz)  
Dielectric constant εeff=13
Cell Parameters a=6.404 Å, b=10.616 Å, c=12.814 Å, z=8.00 Å
Melting Point 1172 ℃
Curie Point 936 ℃
Specific Heat 0.1643 cal/g℃
Angle Acceptance SHG 1064 nm(mrad/cm) 14.2 (Φ)  55.3 (θ)
Clear aperture Centre 90%
Chamfering of edge ≤0.2 mm@45°
Edge breakage ≤0.1 mm
Surface smoothness 10/5
Side perpendicularity ≤5′
Angle tolerance △θ≤0.25°, △ф≤0.25°
laser-damaged threshold: [GW/cm ] >0.5 for 1064 nm, TEM00, 10 ns, 10 HZ (AR-coated)
>0.3 for 532 nm, TEM00, 10 ns, 10 HZ (AR-coated)


  • wide transparency range
  • Stable mechanical and chemical properties
  • Low conductivity
  • highdamage threshold
  • Not easy to deliquesce
  • High temperature stability
  • Large electro-optic coefficient
  • Low half-wave voltage
  • Easy to grow into large crystal


532nm laser

Medical Applications:Evaluation of 532-nm KTP laser treatment efficacy on acne vulgaris
The 532-nm KTP laser is generated by using potassium titanium oxide phosphate (KTiOPO4) for frequency doubling of Nd:YAG laser radiation. This wavelength is appropriate for the treatment of superfi cial vascular and pigmented lesions and used for the treatment of both acne vulgaris and rosacea. For acne vulgaris, photoactivation of bacterial porphyrins, reduction of sebum production and collateral damage to sebaceous glands are the proposed mechanisms for its mode of action.

Medical Applications:Application of potassium-titanyl-phosphate (KTP) laser in the excision of pyriform fossa hemangioma
Among lasers, the KTP-532 laser has several advantages that make it ideally suited for excision of hemangiomas. The potassium-titanyl-phosphate (KTP) laser has a wavelength in the visible light range (532 nm). It does not require an aiming beam and can be delivered via fiberoptic fibers. It is also preferentially absorbed by hemoglobin and, therefore, is effective in the treatment of vascular lesions. KTP-532 laser–assisted excision being a minimally invasive approach provides the advantage of minimal blood loss. The KTP-532 laser offers distinct advantages because it produces a zone of coagulation on either side of the incision, and as it cuts, it appears to seal the edges of the wounds. It is a quick, well-tolerated, minimally invasive procedure. An external incision and scar are avoided with this approach. It is a simple, safe, and effective surgical treatment with great potential in the future.

1 μm radiation of Nd lasers

modulators and Q-switches:KTiOPO4 (KTP) is a relatively new material that is widely used for frequency doubling the 1 μm radiation of Nd lasers.
Its high nonlinear optical d-coefficients, high optical damage threshold, wide acceptance angles and thermally stable phase matching properties make it useful for this purpose and, its large electrooptic r-coefficients and low dielectric constants make it attractive for various electrooptical applications such as modulators and Q-switches.

Nanjing Crylink Photonics Co.,Ltd
No.3, Hengda Road, Economic and Technological Development Zone, Nanjing, China
No.200,Zhaoxian Road,Jiading District,Shanghai City
Tel: (86)025-68790684
Fax: (86)025-68790685
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