Name: stimulated stokes and antistokes raman scattering in microspherical whispering gallery mode resonators
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Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi
Ente Cassa di Risparmio di Firenze (No. 2014.0770A2202.8861)

1.质量微球的超高系数的制作<ol><li>剥去约1-2厘米使用光学脱衣舞标准单模（SMF）石英纤维关闭其丙烯酸涂料。 </li><li>清洁用丙酮剥离的一部分，它劈开。 </li><li>引进尖端切割在熔接机的一只手臂，并产生了一系列使用拼接控制器电弧放电。从捻接器菜单中选择"手动操作"，设置电弧功率电平值和电弧持续时间分别为60和800毫秒;选择"弧"，并推入下方的"+"。 </li><li>一旦球体正在形成，停止，旋转90°的纤维并重复步骤1.3。 </li><li>重复步骤1.3的至少4倍，以获得约160微米的微球体。重复16次，以获得约260微米的微球体。 注:电弓放电将产生熔合石英玻璃所需要的高熔融温度。该面传热Ë紧张将吸引来自缄口不言纤维尖端的球体;球体的大小成正比弧的拍摄张数，在一个直径约为350微米的饱和的，因为它可以在图1中19所示。旋转确保了谐振器的球形。 </li></ol> 2.绘制一个锥形光纤注意:也需要将光耦合进微谐振器的锥形光纤。微球的大小将决定锥度的腰部。为球体直径大于125微米，锥的直径可以是约3-4微米。为较小的，锥形的直径应较小，表示1-2微米。为了保持损失在较低水平，具有在锥形部分只有一个模式（基波之一），锥形必须绝热（从厚到薄直径逐渐过渡）。绝热锥形部的典型总长度约2厘米。Figu重新2显示了自制装置用于拉动光纤和图3A示出一个典型的腰部区域的显微照片。 <ol><li>一个标准单模（SMF）二氧化硅纤维断用光学汽提塔其丙烯酸涂料的条3-4厘米，并连接光纤端部的激光（输入）和功率计（输出）。可以肯定的剥离带是大约在纤维的中间，而不是在一端。使用，以便裸光纤终止，以便能够连接光纤端部到激光和功率计。放置激光器和上工作台顶部的功率计。 </li><li>放置一个短的氧化铝气缸内的剥离的纤维，纤维的成在拉动过程同时启动两个翻译阶段涂覆端部。 </li><li>加热氧化铝缸（充当烘箱）被氧丁烷火焰高达接近二氧化硅的熔点（约2100℃）的温度下。 </li><li>从OBSE推断锥度的绝热在635纳米工作的激光光的透射的rvation。检查在输出而渐缩，表示没有模式加扰发生均匀的圆形光斑被保留。别拉和退役火焰当传输的功率停止振荡，并随时间变化。 </li><li>胶锥形光纤成形为U的形式，以容纳锥形显微镜载玻片（参见图3B）。使用尺寸76x26x1.2毫米的显微镜载玻片。 </li></ol> 3.小微球的制备注:直径包标准光纤的尺寸下面小编球需要纤维变细以前。用这种方法获得的最小直径为大约25微米。 <ol><li>按照第2节，画一个锥形光纤，拉动直到它打破。 </li><li>按照第1（UHQ微球的制备），但在步骤1.3中的所有步骤，修改熔接机共同的价值观ntroller如下:电弧功率20，燃弧时间1200毫秒。 </li></ol> 4.光耦合到微球注意:我们使用锥形将光耦合到微球和测量微谐振器的共振。 <ol><li> 4.1。制备T状的PVC /铝架在中间的信道。修复微球的残留纤维干用一块神奇的苏格兰威士忌或纸胶带为持有人。钳用两个螺钉保持器与压电致动器和20nm的定位分辨率的平移台。 </li><li>固定粘在载玻片与垂直于微纤维的干的滑动面另一平移台锥形。拼接锥度的端部端接光缆。一端连接至所述可调谐激光二极管，另一个到的InGaAs光电二极管检测器。 </li><li>使用显微镜管长工作距离（&gt; 20毫米）到合作ntrol锥度和微球之间的间隙。为了监测系统在另一个方向上发生在45°的反射镜相对于所述管的方向，以使位置可以控制相对于微球的赤道锥度。 <ol><li>在与锥形纤维接触的微球的赤道位置。 </li></ol></li><li>打开激光，并检查微球的锥度系统的透射光谱中的示波器。 <ol><li>调整CW激光器在1550nm波长工作，直到共振出现。共振可以被认定为洛伦兹形频谱骤降。 </li></ol></li><li>测量磁共振行距（洛伦兹形浸全宽度半最大值）。计算Q因子作为所述泵由谐振线宽划分的频率。 </li><li>降低/提高球体和锥体之间的间隙，改变两谐振的宽度和深度为增加/减少的耦合效率。 </li></ol><p类="jove_title"&gt; 5。受激拉曼散射<ol><li>插入CW激光器在1550纳米和衰减器操作之间的掺铒光纤放大器（EDFA）。 EDFA的工作的波长范围内的1,530-1,570纳米。注意:这将促进激光功率，达到2 W.非线性效应的最大输出功率需要很高的输入功率图4显示了实验装置的草图。 </li><li>连接与终止的光纤电缆将一个3 dBm的分离器的锥形的一端。连接分离器输出光纤到光频谱分析仪，另一个给连接到示波器的光检测器中的一个。 </li><li>调由高向低频率的激光直到与媲美的激光的波长扫描速度的热漂移的谐振被发现。当热自锁20取得的共振的扩大可以看出在示波器上。 </li><li>检查通过锥形传输的输出功率成光频谱分析仪。直到出现拉曼激光线增加动力。它从泵波长在约13.5赫兹失谐。 </li></ol>

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The authors declare that they have no competing financial interests. D.F. is a PhD student at the University of Parma.

微球结构紧凑，高效的非线性振荡器和他们很容易制作和处理。锥形光纤可用于耦合，并从共振器抽取/光。能够得到共振造影高达95％和大约3×10 8个 Q因数。 这些制造技术的主要限制是大量生产和集成。纤维的清洁度是两者的微球和锥形关键的，所以是湿度。这两款器件都必须保存在干燥的环境中的长期持久的实验室生活。非常薄的锥度是脆弱的;应十分注意联轴器?...

回音壁模式谐振器（WGMR）显示两个独特的性能，长的光子寿命和小模体积允许的非线性现象1-3阈值的降低。回音壁模式是由全内反射在该介电空中接口局限于光学模式。而在时间限制涉及腔的品质因数Q的小模体积是由于高空间限制。 WGMR可具有不同的几何形状和有适于获得高Q谐振器4-6中表面张力的空腔，如二氧化硅微球显示出邻近原子级粗糙度，转换在高品质的因素不同的制造技术。这两种类型的约束，为非线性效应的门槛降低显著由于在WGMR里​​面强大的能量堆积。它也允许连续波（CW）的非线性光学器件。 WGMR可以用日来说明È量子数N，L，m和它们的偏振态，与所述氢原子7强烈类比。球面对称性允许在径向和角度依赖性的分离。径向溶液通过贝塞尔函数，角那些由球谐8给出。 石英玻璃是中心对称的，因此，相关的Χ二阶现象（2）的相互作用被禁止。在微球体的表面上，对称的反转被破坏和Χ（2）的现象可观察到1。然而，对于第二次频率产生相位匹配条件比在第三次频率代相当于更成问题，尤其是因为所涉及的波长有很大的不同，分散的作用，可以很重要。二阶相互作用极其微弱。所产生的电力尺度与Q 3，而对于THI三阶相互作用所产生的电能秤带Q 4 9出于这个原因，此工作的重点是三阶非线性光学敏感性Χ（3）相互作用如受激拉曼散射（SRS）和受激反斯托克斯拉曼散射（SARS）的，是在非典探索较少互动10,11。昌12和13坎皮略率先使用的高度非线性材料WGMR但泵浦激光器呈脉冲式，而不是CW滴非线性现象研究。相比于微小液滴的二氧化硅微球14,10和microtoroids 15提供更稳定和健壮平台，获得多的注意，在过去几十年。具体地，二氧化硅微球是非常容易制造和处理。 SRS是，可以在二氧化硅WGMR 14,15很容易地实现，因为达到阈值是足够纯的增益处理。在这种情况下，高circulati纳克的WGMR内强度保证拉曼激光，但对于参数振荡是不充分的。在这些情况下，有效的振荡需要相位和模式匹配，能量和动量守恒定律和所有谐振模式的一个良好的空间重叠必须满足16-18。这是SARS和FWM一般的情况下。

<table><tbody><tr><td>Optical Fiber</td><td>Corning</td><td>SMF28</td><td></td></tr><tr><td>Fiber coating stripper</td><td>Thorlabs</td><td>T06S13</td><td>Available from other vendors as well</td></tr><tr><td>Fiber cleaver</td><td>Fitel</td><td>S325A</td><td>Available from other vendors as well</td></tr><tr><td>Fusion splicer</td><td>Furakawa</td><td>S177A-1R</td><td>Available from other vendors as well</td></tr><tr><td>Butane and Oxygen Gas</td><td>n/a</td><td></td><td>any vendor</td></tr><tr><td>Microscope tube</td><td>Navitar</td><td>Zoom 6000</td><td>Modular Kit</td></tr><tr><td>CCD camera</td><td>n/a</td><td>N/A</td><td>any will fit</td></tr><tr><td>Monitor</td><td>n/a</td><td>N/A</td><td>any monitor is valid</td></tr><tr><td>3-Axis Stage</td><td>PI Instruments, Thorlabs, Melles</td><td></td><td></td></tr><tr><td>Assorted posts and mounts</td><td>Thorlabs</td><td></td><td>Available from other vendors as well</td></tr><tr><td>Polarization control</td><td>Thorlabs</td><td>FPC030</td><td>Available from other vendors as well</td></tr><tr><td>Attenuator</td><td>Throlabs</td><td>VOA50</td><td></td></tr><tr><td>Photodiode</td><td>Thorlabs</td><td>PDA400</td><td>discontinued, replaced by PDA10CS-EC</td></tr><tr><td>Oscilloscope</td><td>Tektronix</td><td>DPO7104</td><td></td></tr><tr><td>Optical spectrum analyzer</td><td>Ando</td><td>AQ6317B</td><td></td></tr><tr><td>Erbium Doped Fiber Amplifier</td><td>IPG Photonics</td><td>EAD-2K-C</td><td></td></tr><tr><td>Tunable Laser</td><td>Yenista</td><td>TUNICS</td><td></td></tr></tbody></table>

stimulated stokes and antistokes raman scattering in microspherical whispering gallery mode resonators

介电微球可以只灯光和音响，通过高品质因子回音壁模式一的时间长度（WGM）。玻璃微球可以被认为是能量的存储与一个巨大的各种应用:紧凑激光源，高度敏感的生物化学传感器和非线性现象。一种用于微球体和连接系统两者的制造协议中给出。这里所描述的成色剂是锥形的纤维。有效地产生相关的三阶非线性光学敏感性非线性现象Χ（3）三重谐振二氧化硅微球体的相互作用，提出本文。这里报道的相互作用是:受激拉曼散射（SRS），并且包括受激反斯托克斯拉曼散射（SARS）的四波混合过程。的空腔增强现象的证据是由缺乏泵，信号和闲散之间的相关性的给定:一个谐振模式具有存在以获得一对信号和惰。在hyperparametric振荡的情况下，（四波混频和受激反斯托克斯拉曼散射），模式必须满足能量和动量守恒和最后但并非最不重要的，有一个良好的空间重叠。

微球的Q因素制造按照以上描述的协议是在过量10 8（ 图5），用于大直径（&gt; 200微米）和在过量的10 6个为小直径（&lt;50微米）。 95％（接近临界耦合）上述共振对比可以很容易观察到。对于高循环强度，在红外区域下面的非线性效应可以观察到:受激拉曼散射（SRS），级联的SRS 21，受激反斯托克斯拉曼散射（SARS）和四波混频（FWM）和?...

Watch this Scientific Journal Video about Stimulated Stokes and Antistokes Raman Scattering in Microspherical Whispering Gallery Mode Resonators at JoVE.com

Stimulated Stokes and Antistokes Raman Scattering in Microspherical Whispering Gallery Mode Resonators

刺激斯托克斯和反斯托克斯拉曼散射在微球形回音壁模式谐振器

有效地产生相关的三阶非线性光学敏感性非线性现象Χ（3）三重谐振二氧化硅微球体的相互作用，提出本文。这里报道的相互作用是:受激拉曼散射（SRS），并且包括受激反斯托克斯拉曼散射（SARS）的四波混合过程。

Dielectric microspheres can confine light and sound for a length of time through high quality factor whispering gallery modes (WGM). Glass microspheres ...

stimulated-stokes-antistokes-raman-scattering-microspherical

Universidad de Cartagena UDEC

Research

JoVE Journal

Engineering

11.2K 次观看.  Enrico Fermi Center. 有效地产生相关的三阶非线性光学敏感性非线性现象Χ（3）三重谐振二氧化硅微球体的相互作用，提出本文。这里报道的相互作用是:受激拉曼散射（SRS），并且包括受激反斯托克斯拉曼散射（SARS）的四波混合过程。 

视频: Stimulated Stokes and Antistokes Raman Scattering in Microspherical Whispering Gallery Mode Resonators

Rejection of Fluorescence Background in Resonance and Spontaneous Raman Microspectroscopy

Raman spectroscopy is often plagued by a strong fluorescent background, particularly for biological samples. If a sample is excited with a train of ultrafast pulses, a system that can temporally separate spectrally overlapping signals on a picosecond timescale can isolate promptly arriving Raman scattered light from late-arriving fluorescence light. Here we discuss the construction and operation of a complex nonlinear optical system that uses all-optical switching in the form of a low-power optical Kerr gate to isolate Raman and fluorescence signals. A single 808 nm laser with 2.4 W of average power and 80 MHz repetition rate is split, with approximately 200 mW of 808 nm light being converted to &lt; 5 mW of 404 nm light sent to the sample to excite Raman scattering. The remaining unconverted 808 nm light is then sent to a nonlinear medium where it acts as the pump for the all-optical shutter. The shutter opens and closes in 800 fs with a peak efficiency of approximately 5%. Using this system we are able to successfully separate Raman and fluorescence signals at an 80 MHz repetition rate using pulse energies and average powers that remain biologically safe. Because the system has no spare capacity in terms of optical power, we detail several design and alignment considerations that aid in maximizing the throughput of the system. We also discuss our protocol for obtaining the spatial and temporal overlap of the signal and pump beams within the Kerr medium, as well as a detailed protocol for spectral acquisition. Finally, we report a few representative results of Raman spectra obtained in the presence of strong fluorescence using our time-gating system.

We discuss the construction and operation of a complex nonlinear optical
system that uses ultrafast all-optical switching to isolate Raman from fluorescence
signals. Using this system we are able to successfully separate Raman and fluorescence
signals utilizing pulse energies and average powers that remain biologically safe.

波谱与自发拉曼显微荧光背景的抑制

Raman spectroscopy is often plagued by a strong fluorescent background, particularly for biological samples. If a sample is excited with a train of ...

科研

生物工程

Development of Whispering Gallery Mode Polymeric Micro-optical Electric Field Sensors

Optical modes of dielectric micro-cavities have received significant attention in recent years for their potential in a broad range of applications. The optical modes are frequently referred to as "whispering gallery modes" (WGM) or "morphology dependent resonances" (MDR) and exhibit high optical quality factors. Some proposed applications of micro-cavity optical resonators are in spectroscopy1, micro-cavity laser technology2, optical communications3-6 as well as sensor technology. The WGM-based sensor applications include those in biology7, trace gas detection8, and impurity detection in liquids9. Mechanical sensors based on microsphere resonators have also been proposed, including those for force10,11, pressure12, acceleration13 and wall shear stress14. In the present, we demonstrate a WGM-based electric field sensor, which builds on our previous studies15,16. A candidate application of this sensor is in the detection of neuronal action potential.
The electric field sensor is based on polymeric multi-layered dielectric microspheres. The external electric field induces surface and body forces on the spheres (electrostriction effect) leading to elastic deformation. This change in the morphology of the spheres, leads to shifts in the WGM. The electric field-induced WGM shifts are interrogated by exciting the optical modes of the spheres by laser light. Light from a distributed feedback (DFB) laser (nominal wavelength of ~ 1.3 &mu;m) is side-coupled into the microspheres using a tapered section of a single mode optical fiber. The base material of the spheres is polydimethylsiloxane (PDMS). Three microsphere geometries are used: (1) PDMS sphere with a 60:1 volumetric ratio of base-to-curing agent mixture, (2) multi layer sphere with 60:1 PDMS core, in order to increase the dielectric constant of the sphere, a middle layer of 60:1 PDMS that is mixed with varying amounts (2% to 10% by volume) of barium titanate and an outer layer of 60:1 PDMS and (3) solid silica sphere coated with a thin layer of uncured PDMS base. In each type of sensor, laser light from the tapered fiber is coupled into the outermost layer that provides high optical quality factor WGM (Q ~ 106). The microspheres are poled for several hours at electric fields of ~ 1 MV/m to increase their sensitivity to electric field.

A high-sensitivity photonic micro sensor was developed for electric field detection. The sensor exploits the optical modes of a dielectric sphere. Changes in the external electric field perturb the sphere morphology leading to shifts in its optical modes. The electric field strength is measured by monitoring these optical shifts.

回音壁模式聚合物微光学电场传感器的发展

Optical modes of dielectric micro-cavities have received significant attention in recent years for their potential in a broad range of applications. The ...

工程学

Microwave Photonics Systems Based on Whispering-gallery-mode Resonators

Microwave photonics systems rely fundamentally on the interaction between microwave and optical signals. These systems are extremely promising for various areas of technology and applied science, such as aerospace and communication engineering, sensing, metrology, nonlinear photonics, and quantum optics. In this article, we present the principal techniques used in our lab to build microwave photonics systems based on ultra-high Q whispering gallery mode resonators. First detailed in this article is the protocol for resonator polishing, which is based on a grind-and-polish technique close to the ones used to polish optical components such as lenses or telescope mirrors. Then, a white light interferometric profilometer measures surface roughness, which is a key parameter to characterize the quality of the polishing. In order to launch light in the resonator, a tapered silica fiber with diameter in the micrometer range is used. To reach such small diameters, we adopt the "flame-brushing" technique, using simultaneously computer-controlled motors to pull the fiber apart, and a blowtorch to heat the fiber area to be tapered. The resonator and the tapered fiber are later approached to one another to visualize the resonance signal of the whispering gallery modes using a wavelength-scanning laser. By increasing the optical power in the resonator, nonlinear phenomena are triggered until the formation of a Kerr optical frequency comb is observed with a spectrum made of equidistant spectral lines. These Kerr comb spectra have exceptional characteristics that are suitable for several applications in science and technology. We consider the application related to ultra-stable microwave frequency synthesis and demonstrate the generation of a Kerr comb with GHz intermodal frequency.

The customized techniques developed in our lab to build microwave photonics systems based on ultra-high Q whispering gallery mode resonators are presented. The protocols to obtain and characterize these resonators are detailed, and an explanation of some of their applications in microwave photonics is given.

基于微波光子系统回音壁模式谐振器

Microwave photonics systems rely fundamentally on the interaction between microwave and optical signals. These systems are extremely promising for various ...

Fabrication and Testing of Microfluidic Optomechanical Oscillators

Cavity optomechanics experiments that parametrically couple the phonon modes and photon modes have been investigated in various optical systems including microresonators. However, because of the increased acoustic radiative losses during direct liquid immersion of optomechanical devices, almost all published optomechanical experiments have been performed in solid phase. This paper discusses a recently introduced hollow microfluidic optomechanical resonator. Detailed methodology is provided to fabricate these ultra-high-Q microfluidic resonators, perform optomechanical testing, and measure radiation pressure-driven breathing mode and SBS-driven whispering gallery mode parametric vibrations. By confining liquids inside the capillary resonator, high mechanical- and optical- quality factors are simultaneously maintained.

Parametric optomechanical excitations have recently been experimentally demonstrated in microfluidic optomechanical resonators by means of optical radiation pressure and stimulated Brillouin scattering. This paper describes the fabrication of these microfluidic resonators along with methodologies for generating and verifying optomechanical oscillations.

制造和微流控光机振荡器测试

Cavity optomechanics experiments that parametrically couple the phonon modes and photon modes have been investigated in various optical systems including ...

Resonance Raman Spectroscopy of Extreme Nanowires and Other 1D Systems

This paper briefly describes how nanowires with diameters corresponding to 1 to 5 atoms can be produced by melting a range of inorganic solids in the presence of carbon nanotubes. These nanowires are extreme in the sense that they are the limit of miniaturization of nanowires and their behavior is not always a simple extrapolation of the behavior of larger nanowires as their diameter decreases. The paper then describes the methods required to obtain Raman spectra from extreme nanowires and the fact that due to the van Hove singularities that 1D systems exhibit in their optical density of states, that determining the correct choice of photon excitation energy is critical. It describes the techniques required to determine the photon energy dependence of the resonances observed in Raman spectroscopy of 1D systems and in particular how to obtain measurements of Raman cross-sections with better than 8% noise and measure the variation in the resonance as a function of sample temperature. The paper describes the importance of ensuring that the Raman scattering is linearly proportional to the intensity of the laser excitation intensity. It also describes how to use the polarization dependence of the Raman scattering to separate Raman scattering of the encapsulated 1D systems from those of other extraneous components in any sample.

The paper describes a method for producing extreme nanowires by melt infiltration into carbon nanotubes and how 1D systems may be characterized and investigated using Resonance Raman Spectroscopy to determine vibrational and optical excitation energies.

至尊纳米线和其他维系统的共振拉曼光谱

This paper briefly describes how nanowires with diameters corresponding to 1 to 5 atoms can be produced by melting a range of inorganic solids in the ...

High-speed Continuous-wave Stimulated Brillouin Scattering Spectrometer for Material Analysis

Recent years have witnessed a significant increase in the use of spontaneous Brillouin spectrometers for non-contact analysis of soft matter, such as aqueous solutions and biomaterials, with fast acquisition times. Here, we discuss the assembly and operation of a Brillouin spectrometer that uses stimulated Brillouin scattering (SBS) to measure stimulated Brillouin gain (SBG) spectra of water and lipid emulsion-based tissue-like samples in transmission mode with &lt;10 MHz spectral-resolution and &lt;35 MHz Brillouin-shift measurement precision at &lt;100 ms. The spectrometer consists of two nearly counter-propagating continuous-wave (CW) narrow-linewidth lasers at 780 nm whose frequency detuning is scanned through the material Brillouin shift. By using an ultra-narrowband hot rubidium-85 vapor notch filter and a phase-sensitive detector, the signal-to-noise-ratio of the SBG signal is significantly enhanced compared to that obtained with existing CW-SBS spectrometers. This improvement enables measurement of SBG spectra with up to 100-fold faster acquisition times, thereby facilitating high spectral-resolution and high-precision Brillouin analysis of soft materials at high speed.

We describe the construction of a rapid continuous-wave-stimulated-Brillouin-scattering (CW-SBS) spectrometer. The spectrometer employs single-frequency diode-lasers and an atomic vapor notch-filter to acquire transmission spectra of turbid/non-turbid samples with high spectral-resolution at speeds up to 100-fold faster than those of existing CW-SBS spectrometers. This improvement enables high-speed Brillouin material analysis.

用于材料分析的高速连续波受激布里渊散射光谱仪

Recent years have witnessed a significant increase in the use of spontaneous Brillouin spectrometers for non-contact analysis of soft matter, such as ...

Fabrication of Polymer Microspheres for Optical Resonator and Laser Applications

This paper describes three methods of preparing fluorescent microspheres comprising &#960;-conjugated or non-conjugated polymers: vapor diffusion, interface precipitation, and mini-emulsion. In all methods, well-defined, micrometer-sized spheres are obtained from a self-assembling process in solution. The vapor diffusion method can result in spheres with the highest sphericity and surface smoothness, yet the types of the polymers able to form these spheres are limited. On the other hand, in the mini-emulsion method, microspheres can be made from various types of polymers, even from highly crystalline polymers with coplanar, &#960;-conjugated backbones. The photoluminescent (PL) properties from single isolated microspheres are unusual: the PL is confined inside the spheres, propagates at the circumference of the spheres via the total internal reflection at the polymer/air interface, and self-interferes to show sharp and periodic resonant PL lines. These resonating modes are so-called "whispering gallery modes" (WGMs). This work demonstrates how to measure WGM PL from single isolated spheres using the micro-photoluminescence (&#181;-PL) technique. In this technique, a focused laser beam irradiates a single microsphere, and the luminescence is detected by a spectrometer. A micromanipulation technique is then used to connect the microspheres one by one and to demonstrate the intersphere PL propagation and color conversion from coupled microspheres upon excitation at the perimeter of one sphere and detection of PL from the other microsphere. These techniques, &#181;-PL and micromanipulation, are useful for experiments on micro-optic application using polymer materials.

Protocols for the synthesis of microspheres from polymers, the manipulation of microspheres, and micro-photoluminescence measurements are presented.

用于光学谐振器和激光应用的聚合物微球的制造

This paper describes three methods of preparing fluorescent microspheres comprising &#960;-conjugated or non-conjugated polymers: vapor diffusion, ...

Implementation of a Nonlinear Microscope Based on Stimulated Raman Scattering

Stimulated Raman scattering (SRS) microscopy uses near-infrared excitation light; therefore, it shares many multi-photon microscopic imaging properties. SRS imaging modality can be obtained using commercial laser-scanning microscopes by equipping with a non-descanned forward detector with proper bandpass filters and lock-in amplifier (LIA) detection scheme. A schematic layout of a typical SRS microscope includes the following: two pulsed laser beams, (i.e., the pump and probe directed in a scanning microscope), which must be overlapped in both space and time at the image plane, then focused by a microscope objective into the sample through two scanning mirrors (SMs), which raster the focal spot across an x-y plane. After interaction with the sample, transmitted output pulses are collected by an upper objective and measured by a forward detection system inserted in an inverted microscope. Pump pulses are removed by a stack of optical filters, whereas the probe pulses that are the result of the SRS process occurring in the focal volume of the specimen are measured by a photodiode (PD). The readout of the PD is demodulated by the LIA to extract the modulation depth. A two-dimensional (2D) image is obtained by synchronizing the forward detection unit with the microscope scanning unit. In this paper, the implementation of an SRS microscope is described and successfully demonstrated, as well as the reporting of label-free images of polystyrene beads with diameters of 3 &#181;m. It is worth noting that SRS microscopes are not commercially available, so in order to take advantage of these characteristics, the homemade construction is the only option. Since SRS microscopy is becoming popular in many fields, it is believed that this careful description of the SRS microscope implementation can be very useful for the scientific community.

In this manuscript, the implementation of a stimulated Raman scattering (SRS) microscope, obtained by the integration of an SRS experimental set-up with a laser scanning microscope, is described. The SRS microscope is based on two femtosecond (fs) laser sources, a Ti-Sapphire (Ti:Sa) and synchronized optical parametric oscillator (OPO).

基于刺激拉曼散射的非线性显微镜的实现

Stimulated Raman scattering (SRS) microscopy uses near-infrared excitation light; therefore, it shares many multi-photon microscopic imaging properties. ...

Ultrafast Time-resolved Near-IR Stimulated Raman Measurements of Functional &#960;-conjugate Systems

Femtosecond time-resolved stimulated Raman spectroscopy is a promising method of observing the structural dynamics of short-lived transients with near infrared (near-IR) transitions, because it can overcome the low sensitivity of spontaneous Raman spectrometers in the near-IR region. Here, we describe technical details of a femtosecond time-resolved near-IR multiplex stimulated Raman spectrometer that we have recently developed. A description of signal generation and optimization, measurement, data acquisition, and calibration and correction of recorded data is provided as well. We present an application of our spectrometer to analyze the excited-state dynamics of &#946;-carotene in toluene solution. A C=C stretch band of &#946;-carotene in the second lowest excited singlet (S2) state and the lowest excited singlet (S1) state is clearly observed in the recorded time-resolved stimulated Raman spectra. The femtosecond time-resolved near-IR stimulated Raman spectrometer is applicable to the structural dynamics of &#960;-conjugate systems from simple molecules to complex materials.

Details of signal generation and optimization, measurement, data acquisition, and data handling for a femtosecond time-resolved near-IR stimulated Raman spectrometer are described. A near infrared stimulated Raman study on the excited-state dynamics of &#946;-carotene in toluene is shown as a representative application.

超快时间解析近红外刺激拉曼测量功能 +偶联系统

Femtosecond time-resolved stimulated Raman spectroscopy is a promising method of observing the structural dynamics of short-lived transients with near ...

化学

Multiplex Chemical Imaging Based on Broadband Stimulated Raman Scattering Microscopy

Stimulated Raman scattering (SRS) microscopy is a nonlinear optical technique for label-free chemical imaging. This analytical tool delivers chemical maps at high speed, and high spatial resolution of thin samples by directly interrogating their molecular vibrations. In its standard implementation, SRS microscopy is narrowband and forms images with only a single vibrational frequency at a time. However, this approach not only hinders the chemical specificity of SRS but also neglects the wealth of information encoded within vibrational spectra. 
These limitations can be overcome by broadband SRS, an implementation capable of extracting a vibrational spectrum per pixel of the image in parallel. This delivers hyperspectral data that, when coupled with chemometric analysis, maximizes the amount of information retrieved from the specimen. Thus, broadband SRS improves the chemical specificity of the system, allowing the quantitative determination of the concentration of the different constituents of a sample. Here, we report a protocol for chemical imaging with broadband SRS microscopy, based on a home-built SRS microscope operating with a custom differential multichannel-lock-in amplifier detection. It discusses the sample preparation, alignment of the SRS apparatus, and chemometric analysis. By acquiring vibrational Raman spectra, the protocol illustrates how to identify different chemical species within a mixture, determining their relative concentrations.

We present a protocol to acquire chemical images with broadband stimulated Raman scattering (SRS) microscopy. Based on an SRS microscope that operates with differential multichannel-lock-in detection, the protocol describes the sample preparation, adjustment of the SRS apparatus, and chemometrics to disentangle different constituents of chemically heterogeneous samples.

基于宽带受激拉曼散射显微镜的多重化学成像

Stimulated Raman scattering (SRS) microscopy is a nonlinear optical technique for label-free chemical imaging. This analytical tool delivers chemical maps ...