Barium borate (BBO)

Barium borate (BBO) is a versatile nonlinear crystal, suitable for use in harmonic generation operations, optical parametric oscillators, and in electro-optical applications from the near infrared to the deep ultraviolet. Among BBO’s attractive features are it’s large nonlinear coefficients, high threshold for laser damage, and low thermo-optic coefficient.

At here, high quality BBO single crystals are grown using a top seeded solution growth technique. Our in-house growth, fabrication, and finishing provide unparalleled material traceability and process consistency.

Popular applications of BBO include generating the third, fourth, and fifth harmonics of Nd:YAG lasers (355nm, 266nm, and 213nm respectively), the second and third harmonics of Ti:Sapphire amplifiers (400nm and 266.7nm), and a variety of sum frequency mixing schemes using dye lasers. BBO can be used in OPO configurations to generate tunable output in the visible to near infrared range. BBO is also well suited to Q-switching and other electro-optical applications in high power UV laser systems.

BBO crystal has broad tunability, high damage threshold, and high efficiency. BBO’s small acceptance angle requires a very good beam quality and its large walkoff results in output beams that are very elliptical or slit-like. Type I is usually much more efficient than type II operation. BBO can not be used for NCPM (temperature tuned) application.

Typical applications:
  • SHG ,3HG, 4HG and autocorrelation of femtosecond and picosecond Ti:Sapphire lasers;
  • SHG, 3HG, 4HG, 5HG of YAG lasers at 1064 nm and 1320 nm to yield output of 212-660nm;
  • SHG of tunable dye or solid-state laser sources from 410-750 nm to yield output of 205-375 nm;
  • SFM of dye laser and YAG harmonics to yield output of 189-400 nm;
  • DFM (difference-frequency mixing) from the Visible to the IR range up to over 3000 nm;
  • OPO pumped with SHG or 3HG of YAG or Ti:Sapphire with an output range of 400-3000;
  • Intracavity SHG of Argon ion lasers (488, 514 nm) or Copper vapor lasers (510 nm, 578 nm);
  • Used as E-O crystals in pockels cells

The origin and development of laser

The light source required for fiber-optic communication should be a high-speed modulated light source to carry large-capacity information. Such as lasers and LEDs. The so-called “modulation” is to change the intensity of light, etc., according to the information to be transmitted, to carry information. In 1960, Maimen invented the ruby ​​laser. The difference between laser and ordinary light is that the laser has a very simple optical frequency and has a linear line. In optical, it is called coherent light, and it is most suitable for light source of optical fiber communication. The usual light frequency is very messy and it contains many wavelengths. The usual light frequency is very messy and it contains many wavelengths. The characteristic of coherent light is that the light energy is concentrated, and the divergence angle is small, which is approximately parallel light. After the invention of the ruby ​​laser, various lasers were born: gas lasers, such as helium neon lasers; solid-state lasers, such as YAG yttrium aluminum garnet lasers; chemical lasers; dye lasers. Among them, the semiconductor laser is most suitable for the light source of optical fiber communication. Its small size and high efficiency, its wavelength is suitable for the low loss window of the fiber. However, the manufacturing process of semiconductor lasers is very complicated, and it is necessary to epitaxially grow five layers of doped semiconductor on a substrate material of extremely high purity and defect, and then lithographically illuminate the micron-sized optical waveguide thereon, which has a difficulty compared with the optical fiber. Nothing more than that. In the late 1970s, a semiconductor laser with a long working life at room temperature was finally produced. In 1976, the world’s first practical fiber-optic communication line was established in Atlanta, USA. At this time, the semiconductor laser has not passed, and the light source is a semiconductor light-emitting tube. In the early 1980s, single-mode fibers and lasers were mature, and the superiority of fiber-optic communication capacity was gradually brought into play.
The light emitted by the semiconductor laser is pure, the energy is concentrated, and the beam is very thin. It can efficiently shoot into a single-mode fiber with a core diameter of only 8 microns. Today’s high-speed fiber-optic communication systems use semiconductor lasers as light sources.

True Zero Order Waveplates

The thickness the this type of the true zero-order waveplates or retarders are very thin, the substrates are added to strengthen the waveplates, but in some applications of high damage threshold (>1GW/cm2), the substrates are not allowed, the special carefulness should be taken in operation on such waveplates without substrates.

Hangzhou Shalom EO offer the two types of true zero order waveplates: the singl plate without substrates and the cemented waveplate with substrates. The stocked modules are available for customer’s selection in fast delivery and low cost.

  • True Zero Order Waveplate-Single Plate

This type of zero order waveplate is designed for high damage threshold applocation (more than 1GW/cm2). As the plate is very thin, it’s easy to break during operation.

  • Wide Angle Acceptance
  • Better Temperature Bandwidth
  • Wide Wavelength Bandwidth
  • High Damage Threshold
  • AR Coated, R<0.2%
  • Single Plate

Standard Wavelength:
1/2:1310nm, 1480nm, 1550nm

1/4:980nm, 1064nm,1310nm, 1480nm, 1550nm

  • True Zero Order Waveplate- Cemented

This type of zero order waveplate is constructed of a true zero order waveplate and a BK7 substrate. As the waveplate is very thin and easy to be damaged,the Bk7 plate’s function is to strengthen the waveplate.

  • Standard Thickness:1.1±0.2mm
  • Cemented by Epoxy
  • Wide Angle Acceptance
  • Better Temperature Bandwidth
  • Wide Wavelength Bandwidth
  • AR coating, R<0.2%

Standar wavelength:
532nm, 632.8nm, 780nm, 808nm,980nm, 1064nm,1310nm, 1480nm, 1550nm

Laser Components >> Waveplates >> True Zero Order Waveplates

Hangzhou Shalom Electro-optics Technology Co., Ltd.

Frequently Used Nonlinear Crystal Materials

Frequently Used Nonlinear Crystal Materials

Lithium niobate (LiNbO3) and lithium tantalate (LiTaO3) are materials with a relatively strong nonlinearity. They are often used for nonlinear frequency conversion and also for electro-optic modulators. Both materials are available in congruent and in stoichiometric form, with important differences concerning periodic poling and photorefractive effects (see below). Lithium niobate and tantalate are the most often used materials in the context of periodic poling; the resulting materials are called PPLN (periodically poled lithium niobate) and PPLT, respectively, or PPSLN and PPSLT for the stoichiometric versions. Both have a relatively low damage threshold, but do not need to be operated at high intensities due to their high nonlinearity. They have a tendency for photorefractive effects, which are detrimental for frequency conversion, but are used for, e.g., holographic data storage in Fe-doped LiNbO3 crystals. The tendency for “photorefractive damage” depends strongly on the material composition; e.g. it can be reduced via MgO doping and by using a stoichiometric composition.

Potassium niobate (KNbO3) has a high nonlinearity. It is used for, e.g., frequency doubling to blue wavelengths and in piezoelectric applications.

Potassium titanyl phosphate (KTP, KTiOPO4) may be flux-grown (cheaper) or hydrothermal (better for high powers, lower tendency for gray tracking → photodarkening). The “KTP family” of materials also includes KTA (KTiOAsO4), RTP (RbTiOPO4) and RTA (RbTiAsPO4). These materials tend to have relatively high nonlinearities and are suitable for periodic poling.

Potassium dihydrogen phosphate (KDP, KH2PO4) and potassium dideuterium phosphate (KD*P or DKDP, KD2PO4, exhibiting extended infrared transmission), are available in large sizes at low price. They exhibit good homogeneity over large volumes and have a high damage threshold, but are hygroscopic and have a low nonlinearity.

 

There are a number of borates, the most important ones being lithium triborate (LiB3O5 = LBO), cesium lithium borate (CLBO, CsLiB6O10), β-barium borate (β-BaB2O4 = BBO, strongly hygroscopic, often used in Pockels cells), bismuth triborate (BiB3O6 = BIBO), and cesium borate (CSB3O5 = CBO). Yttrium calcium oxyborate (YCOB) and YAl3(BO3)4 (YAB) are also available in rare-earth-doped form for use as a laser gain medium, and can then simultaneously be used for generating and frequency-converting laser light. Less frequently used are strontium beryllium borate (Sr2Be2B2O7 = SBBO) and K2Al2B2O7 (KAB). LBO, BBO, CLBO, CBO and other borate crystals are suitable for the generation of relatively short wavelengths, e.g. in green and blue laser sources, and for UV generation (→ ultraviolet lasers), because their bandgap energy is relatively high, the crystals are relatively resistant to UV light, and there are suitable phase-matching options. Borates such as LBO and BBO also work well in broadly tunable optical parametric oscillators and optical parametric chirped-pulse amplification.

For mid-infrared (and partly also terahertz) generation, one requires crystal materials with a transparency range extending far into the infrared spectral region. The most important of these media are zinc germanium diphosphide (ZGP, ZnGeP2), silver gallium sulfide and selenide (AgGaS2 and AgGaSe2), gallium selenide (GaSe), and cadmium selenide (CdSe). Gallium arsenide (GaAs) has also become useful for mid-infrared applications, since it is possible to obtain quasi-phase matching in orientation-patterned GaAs .

Sapphire Optics & Custom Sapphire Shapes

Sapphire Lenses, Sapphire Balls, Sapphire Prisms & Mechanical Shapes
Sapphire Optics And Sapphire Custom Shapes, Including Sapphire Balls, Sapphire Lenses, Sapphire Prisms And Mechanical Parts Hold a Unique Place In The World Of Optics. a Sapphire Lens, Ball Lens And Prism All Exhibit Exceptional Performance In a Number Of Applications That Require Extreme Mechanical, Optical, Thermal And Chemical Robustness. Sapphire Optics Also Have Excellent Transmission Bandwidths, Transmitting Well Into The Uv And Ir; a Much Wider Range Than Most Common Lens Materials.

Why Are Sapphire Optics & Sapphire Mechanical Parts Such High Performers?
Sapphire Lenses, Balls & Prisms Are Incredibly Hard, Strong & Wear Resistant:
a Sapphire Lens Can Be Exposed To Extreme Abradants Such As Sand And Particulates With Minimal Effect On The Clarity Of The Optics. This Makes Sapphire Optics The Ideal Material For a Variety Of Applications Such As: Aerospace Lenses, Downhole And Drilling Vision System Optics, Inspection Windows, Watch Crystals And Gun Sights.
Sapphire Lenses And Sapphire Prisms (Optics,Wafers and Crystals >> Sapphire Optics >> Sapphire Prisms) Can Take Pressure Like No Other Clear Material, Making Sapphire Optics The Go-To Transparent Material For Highpressure Vessels, Deep Sea Windows And Sight Glasses. Combined With The Exceptional Thermal And Chemical Performance Of Sapphire, a Sapphire Lens Is The Ideal Transparency For Pressurized In-Process, Deep Sea And Equipment Sensors.

 

FROm: Rayotek Scientific

JUST HOW STRONG ARE SAPPHIRE WINDOWS?

What are Sapphire Windows?
Sapphire Optics is a synthetically grown super hard material that is extremely durable and resistant to scratches. It second only to diamond in terms of its strength. Sapphire windows can withstand more than what quartz and conventional glass can, and at a fraction of the thickness. Sapphire crystals are “grown” in extremely hot ovens. The large, cylindrical boules are cut into sapphire rods, which are then sliced into thin discs, ground, and polished.

Uses of Sapphire Windows
Sapphire windows are used when sapphire’s unique properties – high strength, high scratch resistance, wide optical transmission band, extremely high melt temperature, high thermal conductivity, high electrical resistance and chemical inertness – are required.

Commercial Uses
There are many commercial uses for sapphire. Among the most commonly known are the sapphire display windows that are used to protect the phones’ optics. Newer iPhones use sapphire windows because their fracture toughness is roughly four times greater than Gorilla Glass, which is just strengthened conventional glass. Prior to the smartphone revolution, most consumers’ consumers’ experience of sapphire came from the displays used in most high-end watches.

Optics, Wafers and Crystals

A variety of Optics, wafers and crystals substrates are offered.. Optics products includes: blanks, lenses, windows, prisms and optics made from sapphires, optical glass materials, fluoride crystals and other optical materials., various type of filters for lasers, lighting and biochemical applications and the optical components for IPL equipments. Shalom EO also offers the SAW wafers and substrates made from piezo-electric crystals like LT, LN and quartz, and substrates made from crystals like MgO, GGG, SrTiO3, ect. . The customized optical components for your special applications are available.

Characteristics of compact detectors based on pixellated arrays

Results are presented on the preliminary evaluation of the pixellated NaI(Tl) crystal arrays for use in high-resolution small field-of-view gamma cameras. A prototype detector was developed using the pixellated NaI(Tl) arrays attached to a 5″ diameter position-sensitive photomultiplier tube (PSPMT). Two 5.3 cm square pixellated arrays from Saint-Gobain with pixel sizes of 1/spl times/1/spl times/6 mm and 2/spl times/2/spl times/6 mm were tested. A conventional charge division readout using a resistive chain was used with the PSPMT. The detector was tested using a uniform flood source and a /spl sim/0.8 mm diameter collimated Tc-99m source. The collimated source was scanned over both crystal arrays. The performance characteristics including spatial resolution, energy resolution and the ability to resolve the pixellated crystal elements were determined. The response of the pixellated detector was also measured. With the conventional resistive-chain readout the individual pixels were well resolved for the 2 mm pixellated crystal array but not for the 1 mm pixellated crystal array from the images of a uniform flood source. An average FWHM of 1.4 mm was obtained with a 0.8 mm diameter pencil-beam over the active crystal area for both crystal arrays. The energy resolutions from the individual pixels were 10.8% and 10.0% at 140-keV photon energy for the 1 mm and 2 mm pixellated crystals, respectively. Our study indicates that using conventional resistive-chain readout, a compact detector comprised of a pixellated NaI(Tl) crystal array and a 5″ diameter PSPMT at best can achieve a spatial resolution of /spl sim/1.1 mm. We conclude that the use of pixellated crystal arrays with /spl sim/1.5 mm pixel element is likely to be an optimal choice for the combination of this PSPMT with resistive chain readout technology for development of high resolution small field-of-view gamma cameras.

IR Lenses for Cooled Detectors

IR Lenses for MWIR Cooled Thermal Imaging Cameras
● Aspherical and binary optical technology adoped in design
● Various types of IR materials are used

Hangzhou Shalom Electro‐optics Technology Co., Ltd.

The lenses are designed and used in middle wavelength infrared range (MWIR) thermal imaging cameras of cooled FPA detectors at 3-5μm, with manual or motorized mechanism and in wide range of  focal length, the single FOV and double FOV lenses modules are available. The designed modules are
listed for your selection, and the customs modules are available for customer’s  request.

Modules or Types
The modules are designed for 320 x 256 – 30um/640 x 512 – 15um MWIR cooled detector at  3-5μm.

Features
1.  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.

2. Various type of the infrared materials (like Ge, ZnSe, ZnS, AMTIR, CaF2, Sapphire, BaF2 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.

3. 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.

4. 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).

5. Complete quality assurance system
6. Within our quality system, we works out a series of specific craftworks and develops a strict test  procedure to guarrantee the quality of products.

Properties of scintillators

There are many desired properties of scintillators, such as high density, fast operation speed, low costradiation hardness, production capability and durability of operational parameters. High density reduces the material size of showers for high-energy γ-quanta and electrons. The range of Compton scattered photons for lower energy γ-rays is also decreased via high density materials. This results in high segmentation of the detector and leads to better spatial resolution. Usually high density materials have heavy ions in the lattice (e.g., leadcadmium), significantly increasing the photo-fraction (~Z4).[further explanation needed] The increased photo-fraction is important for some applications such as positron emission tomography. High stopping power for electromagnetic component of the ionizing radiation needs greater photo-fraction; this allows for a compact detector. High operating speed is needed for good resolution of spectra. Precision of time measurement with a scintillation detector is proportional to √τsc. Short decay times are important for the measurement of time intervals and for the operation in fast coincidence circuits. High density and fast response time can allow detection of rare events in particle physics. Particle energy deposited in the material of a scintillator is proportional to the scintillator’s response. Charged particles, γ-quanta and ions have different slopes when their response is measured. Thus, scintillators could be used to identify various types of γ-quanta and particles in fluxes of mixed radiation. Another consideration of scintillators is the cost of producing them. Most crystal scintillators require high-purity chemicals and sometimes rare-earth metals that are fairly expensive. Not only are the materials an expenditure, but many crystals require expensive furnaces and almost six months of growth and analyzing time. Currently, other scintillators are being researched for reduced production cost.

Several other properties are also desirable in a good detector scintillator: a low gamma output (i.e., a high efficiency for converting the energy of incident radiation into scintillation photons), transparency to its own scintillation light (for good light collection), efficient detection of the radiation being studied, a high stopping power, good linearity over a wide range of energy, a short rise time for fast timing applications (e.g., coincidence measurements), a short decay time to reduce detector dead-time and accommodate high event rates, emission in a spectral range matching the spectral sensitivity of existing PMTs (although wavelength shifters can sometimes be used), an index of refraction near that of glass (≈1.5) to allow optimum coupling to the PMT window. Ruggedness and good behavior under high temperature may be desirable where resistance to vibration and high temperature is necessary (e.g., oil exploration). The practical choice of a scintillator material is usually a compromise among those properties to best fit a given application.

Among the properties listed above, the light output is the most important, as it affects both the efficiency and the resolution of the detector (the efficiency is the ratio of detected particles to the total number of particles impinging upon the detector; the energy resolution is the ratio of the full width at half maximum of a given energy peak to the peak position, usually expressed in %). The light output is a strong function of the type of incident particle or photon and of its energy, which therefore strongly influences the type of scintillation material to be used for a particular application. The presence of quenching effects results in reduced light output (i.e., reduced scintillation efficiency). Quenching refers to all radiationless de‑excitation processes in which the excitation is degraded mainly to heat.[5] The overall signal production efficiency of the detector, however, also depends on the quantum efficiency of the PMT (typically ~30% at peak), and on the efficiency of light transmission and collection (which depends on the type of reflector material covering the scintillator and light guides, the length/shape of the light guides, any light absorption, etc.). The light output is often quantified as a number of scintillation photons produced per keV of deposited energy. Typical numbers are (when the incident particle is an electron): ≈40 photons/keV for NaI(Tl), ~10 photons/keV for plastic scintillators, and ~8 photons/keV for bismuth germanate (BGO).

Scintillation detectors are generally assumed to be linear. This assumption is based on two requirements: (1) that the light output of the scintillator is proportional to the energy of the incident radiation; (2) that the electrical pulse produced by the photomultiplier tube is proportional to the emitted scintillation light. The linearity assumption is usually a good rough approximation, although deviations can occur (especially pronounced for particles heavier than the proton at low energies).

Resistance and good behavior under high-temperature, high-vibration environments is especially important for applications such as oil exploration (wireline logging, measurement while drilling). For most scintillators, light output and scintillation decay time depends on the temperature. This dependence can largely be ignored for room-temperature applications since it is usually weak. The dependence on the temperature is also weaker for organic scintillators than it is for inorganic crystals, such as NaI-Tl or BGO. Strong dependence of decay time on the temperature in BGO scintillator is used for remote monitoring of temperature in vacuum environment. The coupled PMTs also exhibit temperature sensitivity, and can be damaged if submitted to mechanical shock. Hence, high temperature rugged PMTs should be used for high-temperature, high-vibration applications.

From Wikipedia, the free encyclopedia

Infared Spherical Lenses(Infared Spherical Lenses)

Hangzhou Shalom EO provides the spherical optical lenses used in thermal imaging cameras at wavelength range MWIR (3-5μm) and LWIR (8-12μm), the lenses are customized and made according to customer’s drawings and requirements. The plano-convex, plano-concave, double convex and meniscus lenses are available, the lens substrates are made from infrared materials: Ge, ZnSe, ZnS, CaF2, BaF2, GaAs, AMTIR glass, Si, Sapphire ect.

thermal imagings\optics for IR lenses\IR Spherical Lenses

 

Features

Optical Lenses works at MWIR (3-5μm) and LWIR (8-12μm) wavelength range;
Substrates materials: Ge, ZnSe, ZnS, CaF2, BaF2, GaAs, AMTIR glass, Si, Sapphire;
Various coating: high-efficiency AR, durable AR and DLC coating are available;
Specifications conformed to military standard.