Single-Crystalline Fibers of Deuterated Potassium Dihydrogen Phosphate

Xueni Liu,Yan Ren,Cheng Qian Zhang,Sheng Qing Xia,Bo Wang

doi:10.3390/cryst10060511

Abstract

Single-crystalline fibers have distinct structures and optical properties comparing with the bulk crystals. In this article, two types of single-crystalline fibers of deuterated potassium dihydrogen phosphate (K(H1−xDx)2PO4, DKDP) are obtained by rapid growth in room-temperature supersaturated solution. X-ray diffraction analysis reveals that these DKDP single-crystalline fibers belong to tetragonal (I-42d) and monoclinic (P21/c) phases, respectively. The crystal structure of the tetragonal DKDP single-crystalline fiber is identical to that of the bulk DKDP tetragonal crystal reported. The lattice parameters of the monoclinic DKDP fiber (with the deuterium content of 55%) are a = 14.6571 Å, b = 4.5187 Å, c = 18.6962 Å, and β = 108.030°, which is a new crystal phase of DKDP. The monoclinic DKDP single-crystalline fiber is metastable at the present experimental condition and readily transit to the corresponding DKDP tetragonal phase in solution and in solid by grinding. The optical experiment shows that the highly deuterated tetragonal DKDP single-crystalline fiber possesses excellent optical guided-wave and effective second-harmonic generation properties. DKDP single-crystalline fibers are expected to be the suitable candidates for fabrication of the miniaturized nonlinear optical devices.

Highlights

Potassium dihydrogen phosphate (KH2 PO4, KDP) and its isotope compound, deuterated potassium dihydrogen phosphate (K(H1−x Dx )2 PO4, DKDP), are irreplaceable electro-optical and nonlinear optical materials in the inertial confinement fusion (ICF) system because of their outstanding capability of growing into large size crystals with high optical quality as well as large nonlinear and electro-optic coefficients [1]
A highly efficient second-harmonic generation was observed in these KDP single-crystalline fibers [3]
The X-ray diffraction analysis is performed in order to determine the crystal structure of these single-crystalline fibers

Summary

Introduction

Potassium dihydrogen phosphate (KH2 PO4, KDP) and its isotope compound, deuterated potassium dihydrogen phosphate (K(H1−x Dx ) PO4 , DKDP), are irreplaceable electro-optical and nonlinear optical materials in the inertial confinement fusion (ICF) system because of their outstanding capability of growing into large size crystals with high optical quality as well as large nonlinear and electro-optic coefficients [1]. We reported the crystal growth of one-dimensional KDP microstructures with a large length-to-diameter ratio grown under the ambient conditions. They exhibit unique crystal growth mechanism, which is quite different from that of the bulk KDP crystals. A highly efficient second-harmonic generation was observed in these KDP single-crystalline fibers [3] The discovery of these one-dimensional KDP materials opens a door to the unknown world of low-dimensional micro-/nano- KDP crystals. It indicates that except for the traditional bulk KDP/DKDP crystals, low-dimensions KDP-type crystals may become another group of robust nonlinear materials, especially for flexible and miniaturized device application in optical communications, high-energy laser, and so on

Methods

Results

Conclusion