高性能Zn扩散掺镁LN晶体脊形波导器件的研究

将铌酸锂(LiNbO_(3),LN)晶体制作成波导型结构能够进一步提高器件的集成度,已经广泛应用于电光调制器、频率变换、声光调Q等光电器件中,在光纤通信、光电传感、激光雷达、航天航空等领域具有重要的应用前景。传统的Ti扩散法制作的LN波导在短波应用中抗光折变损伤能力差,退火质子交换法制作的LN波导只能支持TM模(横磁模)单偏振传输,应用领域受限。本文提出了一种新型Zn扩散法制作掺镁LN脊形波导的方法,通过建立波导的扩散模型和仿真,探索制备的工艺条件并进行测试,得到的LN波导最低传输损耗为0.86 dB/cm,光折变损伤阈值可达到184 kW/cm^(2),这将为高功率铌酸锂波导集成光电器件的研发提供一种较好的制备途径。

Multi-color laser generation in periodically poled KTP crystal with single period

Frequency conversion based on three-wave mixing is a critical nonlinear optic application,extending the frequency range of existing lasers and realizing frequency-transduced detectors in a wavelength range that lacks an effective detector.Phase matching is vital for effective frequency conversion.The advantages of quasi-phase matching(QPM)over birefringent phase matching are a lack of walk-off effect,a maximum nonlinear coefficient,and phase matching in the entire transparency window.Herein,using different types and orders of QPM,four kinds of effective frequency doubling processes are realized in a periodically poled potassium titanyl phosphate(KTP)crystal with a single period,and three kinds of frequency doubling processes are experimentally verified.We also show a feasible way to construct an RGB color generator based on two different QPM processes.This study significantly expands the feasible frequency conversion of existing lasers to different wavelengths,providing an effective method for multi-color laser generation based on periodically poled KTP crystals.

全息模式波前传感器中高阶衍射抑制方法研究

全息模式波前传感器(HWFS)是一种模式型的波前传感器,它利用多模复合的全息元件和位敏探测器来获得入射光中特定模式Zernike像差的强度。然而,多模复合全息元件中的光衍射过程通常会伴随着高阶衍射产生的干扰光。这些干扰光会分散激光能量,降低探测信噪比。提出一种通过引入强度调制的方法来消除由二元相位型全息元件衍射产生的干扰光。该方法不仅可以应用于全息模式波前传感器中干扰光的消除,也适用于其他基于二元相位型全息元件的应用,如全息成像、像移干涉仪、光束偏转器等。