Fluorinated Borate Crystals Deep UV Harmonic Generation

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Solution Overview

Problem

Current nonlinear optical crystals, such as borate crystals, face limitations in UV absorption edge, birefringence, and crystal growth habits, which restrict their performance in deep UV laser applications, particularly in frequency conversion and harmonic generation.

Innovation Solution

Development of ammonium beryllium borate fluoride (NH4Be2BO3F2) and beryllium borate fluoride (Be2BO3F) crystals with trigonal (rhombohedral) structures, which are synthesized using a hydrothermal method, offering improved phase matching and UV absorption characteristics, and overcoming growth habit issues through hydrogen bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If borate nonlinear optical crystals such as BBO, LBO, KBBF are used, then excellent optical properties are achieved, but UV absorption edge and birefringence limitations restrict deep UV laser applications

Engineering Contradiction:

Improveoptical propertiesVSAvoidUV absorption edge limitation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by introducing fluorine atoms into the borate crystal structure, creating fluorinated borate crystals (e.g., K2Be2B2O7, KB2O4) with modified optical properties. This chemical parameter change enables the crystal to achieve a UV absorption edge of 150 nm or lower while maintaining excellent optical properties, thereby resolving the contradiction between optical performance and UV absorption limitations.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If KBBF crystal is used for deep UV applications, then UV absorption edge of 155 nm is achieved, but layered structure causes serious layered habit and very slow growth in z direction

Engineering Contradiction:

ImproveUV absorption edgeVSAvoidcrystal growth

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent creates composite crystal structures by combining potassium, beryllium, boron, and fluorine elements in specific ratios to form fluorinated borate crystals with a new crystal structure. This composite approach results in a non-layered structure that grows uniformly in all directions, eliminating the layered habit problem of KBBF while maintaining the deep UV absorption capability.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If SBBO family crystals are used to overcome layered habit, then crystal growth is improved, but poor structural integrity and optical uniformity limit practical application

Engineering Contradiction:

Improvecrystal growthVSAvoidstructural integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent optimizes the chemical composition parameters by precisely controlling the ratios of K, Be, B, and F elements, and introduces fluorine atoms to strengthen the crystal lattice. This parameter optimization results in fluorinated borate crystals with improved structural integrity and optical uniformity, resolving the contradiction between ease of growth and structural reliability.

Inventive Principle:

Principle #35Parameter changes

4Reliability

If KABO and BABO crystals are used, then structural integrity and optical uniformity are improved, but absorption edge red shifts to 180 nm making them hard to use in deep UV harmonic output

Engineering Contradiction:

Improvestructural integrityVSAvoidabsorption edge red shift

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition by introducing fluorine atoms with high electron density and strong bonding capability. This compositional parameter change shifts the UV absorption edge back to 150 nm or lower while maintaining the structural integrity and optical uniformity achieved in KABO and BABO crystals, thereby enabling deep UV harmonic output applications.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The new crystals exhibit enhanced phase matching ability, shorter UV absorption edges, and improved optical uniformity, enabling efficient harmonic generation across multiple frequencies, including deep UV ranges, and are chemically stable for various nonlinear optical applications.

Implementation Method 1

synthesized using a hydrothermal method

Methodology Applied

Scientific EffectHydrothermal synthesis:

Implementation Method 2

The nonlinear optical effect of a crystal refers to the effect that: when a laser beam having a specific polarization direction passes through a piece of nonlinear optical crystal

Methodology Applied

Scientific EffectNonlinear optical effect:

Implementation Method 3

enhanced phase matching ability

Methodology Applied

Scientific EffectPhase matching:

Implementation Method 4

shorter UV absorption edges

Methodology Applied

Scientific EffectUV absorption: Absorption (EM radiation)

Data Source

PatentUS11898267B2Nonlinear optical crystal fluorine boron beryllium salt and its preparation process and use

Publication Date: 2024.02.13 FUJIAN INST OF RES ON THE STRUCTURE OF MATTER CHINESE ACAD OF SCI

AI summary

Crystalline NH4Be2BO3F2 or Be2BO3F (abbreviated as BBF) has nonlinear optical effect, is not deliquescent in the air, is chemically stable. They can be used in a variety of nonlinear optical fields and will pioneer the nonlinear optical applications in the deep UV band.