Four-wavelength Microdisk Lasers Laterally Coupling to an Output Bus Waveguide

A multiple-wavelength GaInAsP/InP microlaser with microdisk radiuses from 10 m to 10.6 m laterally coupled into a bus waveguide are fabricated by standard photolithygraphy and inductively coupled-plasma (ICP) etching techniques. The lasing wavelengths are 1533 nm, 1541 nm, 1551 nm and 1555 nm at the CW injection current of 10 mA for the four microlasers. The proposed multiple-microlaser array would be useful for realizing compact wavelength division multiplexing (WDM) light source for optical interconnects.

Erbium-ytterbium co-doped lithium niobate single-mode microdisk laser with an ultralow threshold of 1μW

We demonstrate single-mode microdisk lasers in the telecom band with ultralow thresholds on erbium-ytterbium co-doped thin-film lithium niobate(TFLN).The active microdisk was fabricated with high-Q factors by photolithography-assisted chemomechanical etching.Thanks to the erbium-ytterbium co-doping providing high optical gain,the ultralow loss nanostructuring,and the excitation of high-Q coherent polygon modes,which suppresses multimode lasing and allows high spatial mode overlap between pump and lasing modes,single-mode laser emission operating at 1530 nm wavelength was observed with an ultralow threshold,under a 980-nm-band optical pump.The threshold was measured as low as 1μW,which is one order of magnitude smaller than the best results previously reported in single-mode active TFLN microlasers.The conversion efficiency reaches 4.06×10^(-3),which is also the highest value reported in single-mode active TFLN microlasers.

Precise photoelectrochemical tuning of semiconductor microdisk lasers

Micro-and nanodisk lasers have emerged as promising optical sources and probes for on-chip and free-space applications.However,the randomness in disk diameter introduced by standard nanofabrication makes it challenging to obtain deterministic wavelengths.To address this,we developed a photoelectrochemical(PEC)etching-based technique that enables us to precisely tune the lasing wavelength with subnanometer accuracy.We examined the PEC mechanism and compound semiconductor etching rate in diluted sulfuric acid solution.Using this technique,we produced microlasers on a chip and isolated particles with distinct lasing wavelengths.These precisely tuned disk lasers were then used to tag cells in culture.Our results demonstrate that this scalable technique can be used to produce groups of lasers with precise emission wavelengths for various nanophotonic and biomedical applications.

Electrically pumped metallic and plasmonic nanolasers

In recent years, there have been a significant number of demonstrations of small metallic and plasmonic lasers. The vast majority of these demonstrations have been for optically pumped devices. Electrically pumped devices are advantageous for applications and could demonstrate concepts not amenable for optical pumping. However, there have been relatively few demonstrations of electrically pumped small metal cavity lasers. This lack of results is due to the following reasons： there are limited types of electrically pumped gain media available; there is a significantly greater level of complexity required in the fabrication of electrically pumped devices; finally, the required components for electrical pumping restrict cavity design options and furthermore make it intrinsically more difficult to achieve lasing. This review looks at the motivation for electrically pumped nanolasers, the key issues that need addressing for them to be realized, the results that have been achieved so far including devices where lasing has not been achieved, and potential new directions that could be pursued.

增益分布对GaN基蓝光微盘激光器模式分布和发光功率的影响

通过FDTD仿真模拟计算,文中系统地研究了电流阻挡作用对GaN基蓝光激光器增益分布和光学性能的影响,发现回音壁激光模式主要在靠近微盘边缘1.5个波长范围谐振,因此,如果电流阻挡层面积太小,无法最大化减小激光器电流阈值;如果面积太大,回音壁激光模式与无增益区存在耦合效应,从而减少激光功率。另外,随着无增益区域向微盘边缘发生偏移,各个激光模式输出的峰值功率均下降,其中二阶模式峰值功率比一阶模式下降得更加显著,这主要是由于二阶模式分布范围更接近微盘中心区域。同时,进一步发现如果在微盘激光器的仿真模型中引入侧壁缺陷,则将导致边缘无法形成增益区,相比于二阶模式而言,一阶模式的发光功率随侧壁缺陷区域增加而下降的幅度更为显著,这主要是由于一阶模式分布范围更接近微盘边缘。

InGaAsP单量子阱半导体微盘激光器研究

利用普通的液相外延和微加工技术成功地制备了ＩｎＧａＡｓＰ单量子阱微盘激光器，并从实验上观测到远低于普遍激光器阈值条件下的单模振荡，证实了微盘激光器中微盘很强的模式选择作用，反映了微盘的微腔特征．

InGaAsP多量子阱微盘激光器

采用湿法化学腐蚀在气源ＭＢＥＩｎＧａＡｓＰ多量子阱材料上制作了微盘型激光器，直径８μｍ的微盘激光器表现出很好的单模激射特性，阈值泵浦功率为１７０μＷ，激射线宽为１．５ｎｍ．

Mode characteristics of VCSELs with different shape and size oxidation apertures

Vertical cavity surface emitting laser(VCSELs)as the ideal light source for rubidium(Rb)and cesium(Cs)atomic clocks is analyzed for its mode and polarization control.We fabricated three kinds of shapes:triangular,elliptic,and circular oxidation apertures which also have different sizes.We formed three different shape oxide apertures by wetoxidation with 36μm-39μm circular mesa.Our results show that triangular oxidized-VCSEL has the advantages of mode and polarization selection over elliptic and circular oxide apertures.When triangular oxide-confined VCSELs emit in single mode,the measured side mode suppression ratio(SMSR)is larger than 20 d B and orthogonal polarization suppression ratio achieves 10 d B.Resonant blueshift of VCSELs with triangular and elliptic apertures is observed with the decrease of aperture size.

碟型量子阱微腔激光器的低阈值激射

利用反应离子刻蚀 ( RIE)和湿法腐蚀方法在 In Ga As/ In Ga As P多量子阱材料上研制出直径为 8μm、4 .5μm和 2 μm的碟型半导体微腔激光器。其中 2 μm直径的微碟在液氮温度下其光泵浦激射阈值仅为 3 μW左右。对高光功率密度下泵浦时出现的多模激射、跳模和激射光谱强度饱和现象进行了研究。

MOCVD生长InGaAs/InGaAsP多量子阱光泵微碟激光器

用 MOCVD方法生长了 In Ga As/ In Ga As P多量子阱微碟激光器外延片 ,用光刻、干法刻蚀和湿法刻蚀等现代化的微加工技术制备出直径 9.5μm的 In Ga As/ In Ga As P微碟激光器 ,并详细介绍了整个制备工艺过程 .在液氮温度下用氩离子激光器泵浦方式实现了低阈值光泵激射 ,测出单个微碟激光器的阈值光功率为 15 0μW,激射波长约为 1.6μm,品质因数 Q=80 0 ,激射光谱线宽为 2 nm,同时指出微碟激光器激射线宽比 F-

InGaN多量子阱面发射微盘激光器的理论研究

为了实现半导体微盘激光器的单模面发射 ,设计了一种以InGaN多量子阱为有源层 ,GaN外延层为覆盖层的半导体微盘激光器。通过对GaN覆盖层进行图形刻蚀 ,可以对不同的角模式进行有选择的增益 ,由此实现选模。用有效增益因子加电介质盘的模型对实际微盘结构进行简化 ,并根据此模型计算微盘内的场分布和盘外的远场分布 ,并进一步计算有效增益因子。分析表明 ,这种结构能够实现m =1角模式的面发射。

热压法制备的碲酸盐玻璃微盘

提出一种热压法制备微盘激光器的工艺,仅使用实验室常用电阻加热炉具即可制备出不同直径/厚度的微盘激光器.选用TeO2-ZnO-Na2O碲酸盐玻璃为基质材料,制备出直径分布在100-400μm范围内、最小厚度可达8μm、典型品质因数(Q值)约为105的微盘激光器.对碲酸盐玻璃基质材料掺入稀土离子Nd^3+和Tm^3+,通过光纤锥耦合法开展微盘的抽运耦合实验,即可在耦合系统的输出光谱中获得明显的荧光回廊模式和激光模式.以一颗直径为105.74μm、厚度为10.4μm的Nd^3+掺杂微盘为例,当抽运光功率提升至1.364 mW以上时,即可在1.06μm附近获得激光峰.同样实验表明,对Tm^3+掺杂的微盘进行抽运耦合实验可获得1.9μm附近的激光峰.

利用飞秒激光直写技术制备钙钛矿微盘激光器

利用溶液法制备的钙钛矿微/纳米晶虽然可以得到性能良好的微型激光器,但是其所需生长周期较长且缺乏重复性。为了解决这一问题,提出了利用飞秒激光直写技术制备高重复性钙钛矿微盘激光器的新方法。首先使用双源共蒸的方法在石英玻璃衬底上沉积FAPbI_(3)钙钛矿薄膜,然后采用飞秒激光直写技术在FAPbI_(3)钙钛矿薄膜上制备不同直径的微盘激光器,最后测试其激光性能。实验结果表明,随着微盘直径的增加,激光阈值呈线性增长,最终可实现约4.7μJ/cm^(2)的极低激光阈值。利用飞秒激光直写技术制备的钙钛矿微盘激光器具有出色的激光性能,且重复性高,因此该技术非常适用于批量制备钙钛矿微盘激光器,为其产业化应用提供了可能。

耦合微盘及带输出波导的单微盘腔的耦合模式特性

光学微腔具有很高的品质因子和很小的模式体积,在光电子器件研究方面具有重要的应用价值。运用时域有限差分(FDTD)法和Padé近似频谱分析法模拟研究了耦合微盘及带输出波导的单微盘微腔由于空间对称性破坏导致的模式耦合现象;特别计算了耦合模式的场分布和品质因子,并由场分布得出不同角量子数模式的能量比例。对耦合微盘,模式耦合引入的高阶模分量会使耦合模的品质因子大大降低。对半径1μm、折射率3.2的单个微盘,当它连接0.2μm宽度的输出波导时,模式波长相差6.6nm的TE9,1模和TE6,2模耦合形成波长1.52μm的耦合模式,其模式Q值为268,模式具有三角形场分布。

高Q值GaN碟状微米谐振腔的光学特性研究

通过氢化物气相外延(HVPE)方式在蓝宝石衬底上获得了GaN微米碟,其几何形态为规则的正六边形且表面平整,直径约为27μm,高度为15μm。光致发光(PL)实验结果表明,微米碟垂直方向和水平方向的光学谐振模式存在差异,其中水平方向支持回音壁模式(WGM)振荡。在室温条件下采用高能脉冲激光照射微米碟,当激励光功率超过7.8μW时,PL光谱在波长374 nm附近获得多模式激光信号,其中WGM激光占优势,品质因子可达3742。最后采用COMSOL仿真软件对谐振腔进行光场模拟,并分析了其光学模式特性。