Author Affiliations
Abstract
1 School of Instrument Science and Opto-electronic Engineering, Hefei University of Technology, Hefei 230009, China
2 Department of Optics and Optical Engineering, University of Science and Technology of China, Hefei 230026, China
We experimentally demonstrate that optical tweezers can be used to accelerate the self-assembly of colloidal particles at a water–air interface in this Letter. The thermal flow induced by optical tweezers dominates the growth acceleration at the interface. Furthermore, optical tweezers are used to create a local growth peak at the growing front, which is used to study the preferential incorporation positions of incoming particles. The results show that the particles surfed with a strong Marangoni flow tend to fill the gap and smoothen the steep peaks. When the peak is smooth, the incoming particles incorporate the crystal homogeneously at the growing front.
140.7010 Laser trapping 350.4855 Optical tweezers or optical manipulation 230.5298 Photonic crystals Chinese Optics Letters
2017, 15(5): 051401
1 中国科学技术大学光学与光学工程系, 安徽 合肥 230026
2 安徽省光电子科学与技术重点实验室, 安徽 合肥 230026
3 合肥微尺度物质科学国家实验室, 安徽 合肥 230026
光镊技术是激光技术的重大发明，能利用光的动量与物质相互作用产生光势阱效应，已成为微纳米微粒操控和皮牛顿力测量的重要工具。光镊技术不仅丰富和推进了光学领域的发展，也为光学与多学科的交叉融合架起了一座桥梁，彰显出了它独特而不可替代的作用。综述回顾了30 年来光镊理论和技术的发展，系统梳理了光镊在细胞生物学、单分子生物学、软物质胶体科学以及物理纳米科学等领域的应用，并列举典型的应用实例，探讨了光镊技术应用的特点，展望了光镊技术应用蓬勃发展的美好未来。
激光技术 光镊 皮牛顿力测量 活体细胞操控 单分子测量
Author Affiliations
Abstract
Optical tweezers with a low numerical aperture microscope objective is used to manipulate the microspheres at the water-air interface. In this letter, we determine the optimal optical trap for the lateral manipulation of microspheres at a water-air interface. The experimental results show that the trapping force is influenced by the expansion of the trapping beam at the back aperture of the objective. The optimal filling ratio of 0.65 is suggested for lateral optical manipulation at the water-air interface. The lateral trapping forces at the water-air interface are theoretically investigated with the ray-optics model. The numerical results show that the lateral trapping forces can be changed by shrinking the diameter of the trapping laser beam. The numerical results are in accordance with the experimental results.
140.7010 Laser trapping 170.4520 Optical confinement and manipulation 080.5692 Ray trajectories in inhomogeneous media Chinese Optics Letters
2014, 12(1): 011403
Author Affiliations
Abstract
Since RGD peptides (R: arginine; G: glycine; D: aspartic acid) are found to promote cell adhesion, they are modified at numerous materials surface for medical applications such as drug delivery and regenerative medicine. Peptide-cell surface interactions play a key role in the above applications. In this letter, we study the adhesion force between the RGD-coated bead and Hela cell surface by optical tweezes. The adhesion is dominated by the binding of \alpha5\beta1 and RGD-peptide with higher adhesion probability and stronger adhesion strength compared with the adhesion of bare bead and cell surface. The binding force for a single \alpha5\beta1-GRGDSP pair is determined to be 16.8 pN at a loading rate of 1.5 nN/s. The unstressed off-rate is 1.65 \times 10-2 s-1 and the distance of transition state for the rigid binding model is 3.0 nm.
170.1420 Biology 350.4855 Optical tweezers or optical manipulation 140.7010 Laser trapping Chinese Optics Letters
2012, 10(10): 101701
Author Affiliations
Abstract
1 Department of Physics, University of Science and Technology of China, Hefei 230026, China
2 Anhui Key Laboratory for Optoelectronic Science and Technology, Hefei 230026, China
3 Hefei National Laboratory for Physical Sciences at the Microscale, Hefei 230026, China
The transverse trapping forces on a dielectric sphere located at an oil-water interface are theoretically investigated with the ray-optics model. The transverse trapping forces rely on the internal property of the particle-interface system, and increase with either the decrease of three phase contact angles at the oil-water interface or the use of oil phase with low refractive index. The numerical results also show that the transverse trapping forces can be improved by either decreasing the numerical aperture of the microscope objective or shrinking the diameter of the trapping laser beam.
光镊 油-水界面 几何光学模型 140.7010 Laser trapping 080.5692 Ray trajectories in inhomogeneous media Chinese Optics Letters
2010, 8(7): 673
Author Affiliations
Abstract
1 Hefei National Laboratory for Physical Sciences at the Microscale, Heifei 230026, China
2 Department of Physics, University of Science and Technology of China, Hefei 230026, China
3 Anhui Key Laboratory for Optoelectronic Science and Technology, University of Science and Technology of China, Hefei 230026, China
The Brownian motion of a polystyrene bead trapped in a time-sharing optical tweezers (TSOT) is numerically simulated by adopting Monte-Carlo technique. By analyzing the Brownian motion signal, the effective stiffness of a TSOT is acquired at different switching frequencies. Simulation results confirm that for a specific laser power and duty ratio, the effective stiffness varies with the frequency at low frequency range, while at high frequency range it keeps constant. Our results reveal that the switching frequency can be used to control the stability of time-sharing optical tweezers in a range.
时分复用 光镊 蒙特卡洛 有效刚度 120.4640 Optical instruments 250.4110 Modulators 250.6715 Switching Chinese Optics Letters
2010, 8(2): 170
1 中国科学技术大学 物理系,安徽 合肥 230026
2 西北大学 物理学系,陕西 西安 710069
3 合肥微尺度物质科学国家实验室,安徽 合肥 230026
利用光镊捕获单个微小粒子,在各个研究领域得到重要应用。光镊也能同时捕获两个或更多个粒子,明确地知道光阱中粒子的个数,是顺利进行研究的前提。根据光散射原理,提出通过测量阱域内微小粒子的背散光强度来区分光阱中的粒子个数,实验上成功地实现了对直径分别为1 μm,0.5 μm,0.2 μm,100 nm和73 nm的被捕获于光阱中的粒子个数的分辨。对背散光光强随着粒子直径变化所反映的信息进行了分析,讨论了光阱中多粒子的排列状态。通过背散光实时动态分辨光阱中的纳米粒子个数的实验方法,对将光镊扩展到纳米尺度的应用提供了技术支持。
激光光学 光镊 背散光 纳米粒子个数
本文介绍了激光喇曼光谱法诊断火焰的基本原理和实验方法。运用该方法可以测得火焰的温度和物质浓度的三维空间场分布。实验结果与实际情况相符合。
