Calcium Fluoride (CaF2) Windows

  • UV to IR wavelength range 0.18-8 μm
  • Excellent as the security inspection windows      


Due to its high average transmission and low chromatic aberration relative to other IR materials, calcium fluoride(CaF2 ) is an excellent choice for windows and lenses for spectroscopy applications in the deep UV to near IR wavelength range (180 nm-8 µm). For its good transmission properties at LWIR range, the CaF2 are often selected as the windows for thermal imaging security inspections in electric power facilities and petroleum industries. A protective coated could be made on the windows surface to improve its deliquescence properties.


The Choice of Nonlinear Crystals

Many different properties of a nonlinear crystal can be important for an application e.g. in nonlinear frequency conversion:

The chromatic dispersion and birefringence properties determine the possibilities for phase matching and the phase-matching bandwidth, angular acceptance (for critical phase matching), etc.
The magnitude of the effective nonlinear coefficient deff, which depends on the nonlinear tensor components and on the phase-matching configuration, is important particularly if the achievable optical intensities are low.
Normally, the crystal material should have a high optical transparency for all wavelengths involved.

Additional properties can be relevant for a comparison:

the material’s potential to be periodically poled to achieve quasi-phase matching
linear absorption, which can cause heating at high optical power levels, so that the phase matching is disturbed, and thermal lensing may occur
the resistance against optical damage, gray tracking, photodarkening, green-induced infrared absorption, and the like
the resistance against photorefractive effects (which are often called photorefractive damage, even though this is usually reversible)
the availability of crystals with consistently good quality, large size and a reasonable price
the ease of fabricating high-quality anti-reflection coatings on the crystals
the chemical durability; e.g., some crystal materials are hygroscopic, others undergo chemical changes when heated in a vacuum chamber for application of a dielectric coating
The choice of the most suitable crystal material for a given application is often far from trivial; it should involve the consideration of many aspects. For example, a high nonlinearity for frequency conversion of ultrashort pulses does not help if the interaction length is strongly limited by a large group velocity mismatch and the low damage threshold limits the applicable optical intensities. Also, it can be highly desirable to use a crystal material which can be critically phase-matched at room temperature, because noncritical phase matching often involves the operation of the crystal in a temperature-stabilized crystal oven.

Zero Order Waveplates For UV – Optically Contacted

These zero order waveplates are made from two pieces of quartz, either cemented or optically contacted, with their optic axes perpendicular to each other. Their thicknesses are slightly different in order to provide a net zero order retardation. They can be used to change the state of polarization of incident light. A quarter wave plate has a net retardation of pi/2 and changes polarization from linear to circular or circular to linear. A half wave plate has a net retardation of pi and rotates the plane of polarization by 90deg. These waveplates are available either unmounted or mounted in a metal ring.

Cr4+:YAG Crystals

Laser Components >> Passive Q-switch Crystals

  • Simple to use, no need of external driving system
  • Compact setup
  • Working frequency upto 10kHz


Chromium Doped Yttrium Aluminum Garnet (Cr4+:YAG) Crystal is excellent E-O material for passively Q-switching diode pumped or lamp-pumped Nd:YAG, Nd:YLF, Nd:YVO4 and other Nd (or Yb) doped lasers at 0.8~1.2µm. With the advantages of chemically stable, durable, UV resistant, good thermal conductivity, high damage threshold ( >500 MW/cm2) and easy operation, Cr4+:YAG is edging out traditional materials, such as LiF, organic Dye and color centers.

Dimensions range Surface Area 2×2 mm2~ 14×14mm2
Length 0.1mm ~ 12mm
Doping Concentration 0.03mol% ~ 0.65mol%
Initial Transmission 5% ~ 95%
Flatness < λ/10 @633nm
Wavefront Distortion < λ/6 @633nm
Parallelism < 30″
Surface Quality 10/5 S/D (per MIL-O-13830A)
AR coating R<2% @ 1064nm or 1053nm


Physical and optical Properties
Chemical Formula Cr4+:Y3A15O12
Crystal Structure Cubic Garnet
Density 4.56g/cm3
Hardness 8.5 Mohs
Damage Threshold > 500 MW/cm2
Regractive Index 1.82 @ 1064 nm

OASIS 7 International Conference and Exhibition with Shalom EO

Thanks for inviting Shalom EO to attend such as a grand ceremony. We met many closedcustomers and friends. And we hope can continue good cooperative relations with you!!

Thanks a lot for all of you!!

Hangzhou Shalom Electro-optics Technology Co., founded in 2011, the founder James Tang have worked as optics engineer and optics sales manager for more than 25 years, our expert group will offer excellent service to you. Shalom EO is located Hangzhou, a beautiful touring city, about 200Km from Shanghai. Hangzhou is a famous city with long history, it is also well known for its high-tech industry in IT, optical fiber communications and E-commerce, the headquarters of Alibaba is located in Hangzhou.

Infrared Optics

Laser Components


Wafers and Substrates

Zero-Order Waveplates

Waveplates are used in the synthesis and analysis of polarized light. Quarter Waveplates transform linearly polarized light into circularly polarized light, and vice-versa. Half Waveplates rotate the plane of polarization of linearly polarized light through any angle. They also convert left circularly polarized light into right circularly polarized light, and vice-versa.

Zero-Order Waveplates are made from two Crystalline Quartz or Sapphire plates of similar thickness, that are optically contacted together with orthogonally aligned optical axes.

Retardation varies slowly with wavelength, thus they are useful with tunable or broadband sources. Retardation is a function of thickness difference between the two plates, and is essentially invariant with temperature.

Laser Components >> Waveplates >> Zero Order Waveplates


IR Lenses for 640×480-25um LWIR FPA Detectors

● Aspherical and binary optical technology adoped in design
● Various types of IR materials are used
● Some stocked modules available in fast delivery and low cost
The IR lenses are designed for 640×480-25μm FPA detectors used in long wavelength infrared range (LWIR) uncooled thermal imaging cameras, with manual or motorized mechanism and in wide range of focal length, the single FOV, double FOV and continuous zoom lenses are available. The listed designed modules are ready for your selection and the customs modules are available upon customer’s request

 Aspheric Technology and Binary Optics Technology are used in design, which effectively reduce the spherical aberration, distortion and other various aberrations, achieve athermalization design and reduce the number of needed lens elements, lower the cost.
 Various type of the infrared materials (like Ge, ZnSe, ZnS,AMTIR ect.) are used in the lenses, which would successfully eliminate the aberration of the image and improve the quality of imaging, especially for the large diameter telephoto lenses.
 Advanced equipment and machines are used to process the infrared materials optics: ultra-precision single point diamond processing machine to achieve the precision aspheric in 3nm, diffractive surface processing equipment to process the Ge, ZnSe, ZnS and AMTIR materials.
 Different types of coating are made on the lens optics: high-efficiency anti-reflection coating (or high-efficiency AR), durable anti-reflection coating (or Durable AR) and diamond-like hard carbon coating (or DLC coating).
 Complete quality assurance system Within our quality system, we works out a series of specific craftworks and develops a strict test procedure to guarrantee the quality of products.

Crystal optics

The study of the propagation of light, and associated phenomena, in crystalline solids. For a simple cubic crystal the atomic arrangement is such that in each direction through the crystal the crystal presents the same optical appearance. The atoms in anisotropic crystals are closer together in some planes through the material than in others. In anisotropic crystals the optical characteristics are different in different directions. In classical physics the progress of an electromagnetic wave through a material involves the periodic displacement of electrons. In anisotropic substances the forces resisting these displacements depend on the displacement direction. Thus the velocity of a light wave is different in different directions and for different states of polarization. The absorption of the wave may also be different in different directions. See Dichroism, Trichroism

In an isotropic medium the light from a point source spreads out in a spherical shell. The light from a point source embedded in an anisotropic crystal spreads out in two wave surfaces, one of which travels at a faster rate than the other. The polarization of the light varies from point to point over each wave surface, and in any particular direction from the source the polarization of the two surfaces is opposite. The characteristics of these surfaces can be determined experimentally by making measurements on a given crystal.

In the most general case of a transparent anisotropic medium, the dielectric constant is different along each of three orthogonal axes. This means that when the light vector is oriented along each direction, the velocity of light is different. One method for calculating the behavior of a transparent anisotropic material is through the use of the index ellipsoid, also called the reciprocal ellipsoid, optical indicatrix, or ellipsoid of wave normals. This is the surface obtained by plotting the value of the refractive index in each principal direction for a linearly polarized light vector lying in that direction . The different indices of refraction, or wave velocities associated with a given propagation direction, are then given by sections through the origin of the coordinates in which the index ellipsoid is drawn. These sections are ellipses, and the major and minor axes of the ellipse represent the fast and slow axes for light proceeding along the normal to the plane of the ellipse. The length of the axes represents the refractive indices for the fast and slow wave, respectively. The most asymmetric type of ellipsoid has three unequal axes. It is a general rule in crystallography that no property of a crystal will have less symmetry than the class in which the crystal belongs.

Accordingly, there are many crystals which, for example, have four- or sixfold rotation symmetry about an axis, and for these the index ellipsoid cannot have three unequal axes but is an ellipsoid of revolution. In such a crystal, light will be propagated along this axis as though the crystal were isotropic, and the velocity of propagation will be independent of the state of polarization. The section of the index ellipsoid at right angles to this direction is a circle. Such crystals are called uniaxial and the mathematics of their optical behavior is relatively straightforward.

In crystals of low symmetry the index ellipsoid has three unequal axes. These crystals are termed biaxial and have two directions along which the wave velocity is independent of the polarization direction. These correspond to the two sections of the ellipsoid which are circular. See Crystallography

The normal to a plane wavefront moves with the phase velocity. The Huygens wavelet, which is the light moving out from a point disturbance, will propagate with a ray velocity. Just as the index ellipsoid can be used to compute the phase or wave velocity, so can a ray ellipsoid be used to calculate the ray velocity. The length of the axes of this ellipsoid is given by the velocity of the linearly polarized ray whose electric vector lies in the axis direction. See Phase velocity

The refraction of a light ray on passing through the surface of an anisotropic uniaxial crystal can be calculated with Huygens wavelets in the same manner as in an isotropic material. For the ellipsoidal wavelet this results in an optical behavior which is completely different from that normally associated with refraction. The ray associated with this behavior is termed the extraordinary ray. At a crystal surface where the optic axis is inclined at an angle, a ray of unpolarized light incident normally on the surface is split into two beams: the ordinary ray, which proceeds through the surface without deviation; and the extraordinary ray, which is deviated by an angle determined by a line drawn from the center of one of the Huygens ellipsoidal wavelets to the point at which the ellipsoid is tangent to a line parallel to the surface. The two beams are oppositely linearly polarized.

IR Sapphire Windows

Sapphire (Al₂O₃) is an incredibly hard crystal (HK1370kg/mm2), second only to diamond. It has high mechanical strength, thermal and chemical resistance and is scratch resistant, making it very desirable for operating in harsh conditions. Sapphire windows can be made thinner than alternative crystals thanks to its structural integrity and can operate up to 2030⁰C. The material transmits between the UV and IR at 0.15-5.5µm, and has a high refractive index of 1.75..q

Sapphire has applications where its strength and durability are required. This includes pressure optical windows, furnace viewports, submersible ROVs, gas and oil analysis, barcode readers and IR analytical devices.

Optical grade LiNbO3 wafers

The Optical grade LiNbO3 wafers/crystals/substrates are offered, advanced facilities are equipped for crystals growing, wafer cutting, lapping, polishing and checking. The LiNbO3 wafers are used in: 

  • Polarizers for Optic Isolators;
  • Integrated Waveguide Photonics;
  • EO Waveguide Phase Modulators
  • EO Waveguide Amplitude Modulators
  • Quasi-phase Matching for SHG and OPO

Optical grade LiNbO3 wafers of X-cut and Z-cut

Orientation X-cut±0.2° Z-cut±0.2°
Diameter 76.2mm±0.3mm




Orientation Flat(OF) 22mm±2mm


Perpendicular to X±0.2°



Perpendicular to X±0.2°

Second Refer Flat(RF) Cw225°±0.5°from OF

Cw315°±0.5°from OF

Cw225°±0.5°from OF

Cw270°±0.5°from OF

Thickness 500μm±5μm




Surface quality Double sides polished

S/D 20/10

Double sides polished

S/D 20/10

TTV ≤10μm
WARP ≤50μm
Curie Temperature 1142℃±0.7℃
Refractive Index n0=2.2878±0.0002 ne=2.2033±0.0002

prism coupler method @632.8nm

Edge Beveling Edge rounding

Note: The other size or type of LiNbO substrates or wafers are available upon customer’s request.