Er,Yb co-doped yttrium aluminum tetraborate laser crystal

Er:Yb:YAl₃(BO₃)₄ Crystal

BBO crystal (β-Barium Borate, β-BaB₂O₄), a trigonal non-centrosymmetric nonlinear optical crystal, is renowned for generating 2nd–5th harmonics of Nd:YAG lasers with efficiencies up to 70% (SHG, 532 nm), 60% (THG, 355 nm), 50% (FHG, 266 nm), and a record 200 mW at 213 nm (FFHG). Its superior performance stems from a broad transparency range (189–3500 nm), high nonlinear coefficient (d₁₁ = 2.6 pm/V at 1064 nm→532 nm), low photorefractivity, and non-hygroscopicity, making it critical for UV lithography, laser micromachining, and medical optics.

LBO Crystal, short for Lithium Triborate Crystal, is a remarkable nonlinear optical crystal. With a chemical formula of LiB₃O₅, it features a wide transparency range from 155 to 3200 nm, allowing interaction with diverse laser sources. It has a high damage threshold, capable of withstanding intense laser beams without performance degradation, which is crucial for high - power laser applications. LBO Crystal also shows excellent optical homogeneity. It's widely used in frequency doubling, tripling of high - peak - power pulsed lasers, and optical parametric oscillators. Its outstanding properties make it an essential component in optical systems like medical lasers, laser displays, and optical data storage.

KTP Crystal is mostly used as nonlinear crystals for frequency doubling of solid-state Nd:YAG crystal or Nd:YVO4 crystal laser, as it has large nonlinear optical coefficients, wide angular bandwidth and small walk-off angle, broad temperature and spectral bandwidth. KTP crystal also has high electro-optic(E-O) coefficient and low dielectric constant, and large figure of merit, these features make it also widely used in electro-optic application.

Periodically Poled Potassium Titanyl Phosphate (PPKTP) crystal is a ferroelectric nonlinear crystal with a unique structure, which aids in efficient frequency conversion through Quasi - Phase - Matching (QPM). The crystal is composed of alternating domains with spontaneous polarization of opposite orientations, enabling QPM to correct the phase mismatch in nonlinear interactions. The crystal is suitable for efficient conversion of any nonlinear process within its transparency range.

Lithium Niobate (LiNbO3) 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 LiNbO3 crystal. Also LiNbO3 Crystal is widely used as frequency doublers for wavelength >1um and optical parametric oscillators (OPO) pumped at 1064 nm as well as quasi-phase-matched (QPM) devices.

Periodically Poled LN (PPLN) Crystal is formed by fabricating the nonlinear optical crystal lithium niobate (LN) into a periodically reversed domain structure, based on the quasi - phase matching theory (QPM). This unique structural design enables specific optical properties critical for nonlinear optical applications.

Potassium Dihydrogen Phosphate (KDP, KH₂PO₄) and Potassium Dideuterium Phosphate (KDP, KD₂PO₄) are tetragonal nonlinear optical crystals widely used for second (532 nm, 60% efficiency), third (355 nm), and fourth harmonic generation (266 nm) of Nd:YAG lasers via type I/II phase matching at room temperature, with KDP offering 75% SHG efficiency and higher damage threshold via deuteration. As electro-optic materials, they feature ultra-high coefficients (r₃₃=23.3 pm/V for KDP), low half-wave voltage (~7.6 kV at 1064 nm), and broad bandwidth (>10 GHz), enabling applications in Pockels cells, modulators, and high-power laser systems like inertial confinement fusion, where KDP’s non-hygroscopicity outperforms KDP in harsh environments.

Calcite (CaCO₃), a trigonal negative uniaxial crystal with extreme birefringence and broad transmission (200 nm–2300nm), is the premier material for visible-near infrared polarizing optics despite its softness (Mohs 3) and hygroscopicity. It enables Glan–Taylor/Thompson polarizers with extinction ratios >10⁶:1, beam displacers, and UV wave plates, outperforming synthetic crystals like YVO₄ in the ultraviolet range but requiring AR coatings and humidity control.

The yttrium orthovanadate (YVO4) is a positive uniaxial crystal grown with Czochralski method. It has good mechanical and physical properties and is ideal for optical polarizing components because of its wide transparency range and large birefringence. It is an excellent synthetic substitute for Calcite (CaCO3) and Rutile (TiO2) crystals in many applications including fiber optic isolators and circulators, beam displacers, Glan polarizers and other polarizing optics, etc.

High Temperature form BBO (a-BaB2O4) is a negative uniaxial crystal.It has large birefringence over the broad transparent range from 189 nm to 3500 nm.Recently,MT-Optics has succeeded in growing this crystal into large size.The physical,chemical,thermal and optical properties of a-BBO crystal are similar to those of β-BBO.However,the nonlinear optical properties of a-BBO crystal is vanished due to the centric symmetry with its crystal structure,it is not recommended or NLO processes.

Neodymium doped Gadolinium Vanadate (Nd:GdVO4 crystals) belonging to the tetragonal crystal system, is an excellent ideal laser host material for DPSS (Diode Pumped Solid State) micro/mini lasers. It exhibits remarkable physical, optical, and mechanical properties. In terms of laser performance, Nd:GdVO4 crystals demonstrate higher slope efficiency compared to Nd:YAG crystals. When contrasted with Nd:YVO4 crystals, they possess superior thermal conductivity, enabling more stable operation under high-power conditions, and can achieve higher power output. Moreover, its distinct optical anisotropy facilitates efficient polarization control in laser systems. These characteristics make Nd:GdVO4 crystals highly suitable for applications in compact laser devices, such as medical laser equipment, precision laser processing systems, and advanced scientific research laser setups, where high efficiency and stable performance are critical requirements.

Potassium Gadolinium Tungstate (KGd(WO₄)₂) crystal features a broad transmission range, excellent thermal conductivity, a high damage threshold, a large Raman shift coefficient and a high Raman gain. As an outstanding stimulated Raman laser crystal, it can maintain high conversion efficiency and beam quality during Raman frequency conversion.

Er:Yb:YAl₃(BO₃)₄ crystal: is currently the Er,Yb co-doped laser material with the best comprehensive performance in the 1.55 μm band. Compared with Er,Yb co-doped phosphate glass, it enables continuous-wave laser operation with higher output power and higher slope efficiency. Lasers at the 1.55 μm band are eye-safe, lie within the atmospheric transmission window and the minimum loss window of silica fibers, possess strong penetration through smoke and fog, and match the detection sensitive regions of room-temperature Ge and InGaAs detectors. They can be used in laser ranging, velocity measurement, 3D imaging, target recognition and other fields.

Nd:YVO4 is one of the most efficient laser host crystals currently existing for diode laser-pumped solid-state lasers. Its large stimulated emission cross-section at lasing wavelength, high absorption coefficient and wide absorption bandwidth at pump wavelength, high laser induced damage threshold as well as good physical, optical and mechanical properties make Nd:YVO4 an excellent crystal for high power, stable and cost-effective diode pumped solid-state lasers.

Terbium Gallium Garnet (TGG) is the rightcrystal material for Farady devices(Rotator and Isolator). The Farady ratatoris made up of a TGG rod contained in a special designed magnet. Thepolarization of a light beam passing through the rotator makes rotation.Thedirection of rotation is only dependent on the direction of the magnetic fieldand not on the direction of propagation of the light beam.The optical isolatorconsists of a 45 degree rotator set between two suitably arrayed polarizerswhich allow a light beam to pass through in one direction only. With acombination of excellent properties, such as large verdet constant,low lightloss, high thermal conductance and high light damage threshold,TGG is theunique material for Farady devices. It is widely used for YAG lasers andTi:sapphire tunable lasers,ring Lasers,etc.

Cr⁴⁺:YAG Crystal is a crystal with excellent performance as a passive Q - switch for Nd:YAG, Nd:YLF, Nd:YVO₄, and other neodymium - doped or ytterbium - doped lasers with wavelengths from 0.8 to 1.2μm. With a passive Q - switch or saturable absorber, sufficient laser pulses can be obtained without the need for an electro - optical switch. Due to its good chemical stability, durability, UV resistance, good thermal conductivity, high damage threshold (>500MW/cm²), and ease of handling, it will replace the commonly used LiF and dyes in the field of passive Q - switches and become an excellent choice for 1μm Nd - doped lasers.