Mg₃B₇O₁₃Cl: A New Quasi‐Phase Matching Crystal in the Deep‐Ultraviolet Region

Abstract

Deep-ultraviolet lasers play an important role in many scientific and technical fields, the generation of which by means of the nonlinear optical frequency conversion technology attracted immense research interest over the past few decades. Up to now, there are few nonlinear optical crystals, except KBe 2 BO 3 F 2 , which could produce deep-ultraviolet coherent light by a harmonic generation process. However, industrialization of KBe 2 BO 3 F 2 is hampered by its layering growth habit and weak interlayer force. Here, a new deep-ultraviolet nonlinear optical crystal, Mg 3 B 7 O 13 Cl, is found, which will be a good candidate for deep-ultraviolet coherent generation. It crystallizes an acentric space group of Pca2 1 at room temperature with both 3D borate frameworks and distorted octahedrons, which makes it a unity of optical nonlinearity and ferroelectricity. Furthermore, a short absorption cutoff of 155 nm, a second harmonic generation coefficient of 0.38 pm V −1 , a coercive field of 21.2 kV cm −1 , and a remanent polarization of 0.36 µC cm −2 for Mg 3 B 7 O 13 Cl crystal are identified. These features indicate that Mg 3 B 7 O 13 Cl crystal can generate deep-ultraviolet coherent light by a quasi-phase matching technique with a periodically poling method. This pioneering and profound work points out a new research area in the development of deep-ultraviolet lasers.

Pushing periodic-disorder-induced phase matching into the deep-ultraviolet spectral region: theory and demonstration

“…First, we compared the basic properties of nine DUV transparent nonlinear optical crystals that have a short ultraviolet transparent cutoff wavelength 18,[26][27][28][29][30] to meet the primary requirement for APP crystals, as depicted in Fig. 4a.…”

β‐CsB9O14: A Triple‐Layered Borate with Edge‐Sharing BO4 Tetrahedra Exhibiting a Short Cutoff Edge and a Large Birefringence

“…Borates, especially, can be regarded as an excellent candidate to explore structure unique compounds due to various coordination pattern of B (BO 3 or BO 4 ) which may be polymerized to form different fundamental building blocks (FBBs). Then the FBBs will further construct isolated clusters, one‐dimensional (1D) chains, 2D layers, or 3D networks . The abundant structures of borates are deemed to be the major factor in their optical properties.…”

Emergent Deep‐Ultraviolet Nonlinear Optical Candidates

“…[11] In addition, BaMgF 4 and Mg 3 B 7 O 13 Cl crystals are expected to emit deep-UV laser light lasers by QPM technology. [12,13] However, the complexity of SFG laser systems and the intrinsically irregular behavior in the QPM process hinder their wide application. By contrast, the SHG method to produce deep-UV coherent lasers is more attractive and has thus attracted much attention.…”