宣传册
将拉曼光谱扩展至太赫兹频段
一次测量即可同时获取化学成分和结构信息
化学性质与结构性质的同步测量
Coherent-patented1 THz-Raman™ systems boost both the efficiency and reliability of materials characterization, in a single, real-time, non-destructive measurement. By unveiling the low-frequency (low wavenumber) range of the Raman spectrum, often referred to as a secondary “structural fingerprint,” it is possible to directly observe and differentiate key structural properties of materials, while preserving the complete chemical fingerprint.
主要应用包括：
太赫兹拉曼波段（±5 cm⁻¹ 至 200 cm⁻¹）对应于分子间/分子内振动的太赫兹能量振动（150 GHz 至 6 THz），包括声子模、晶格模和旋转模。这些振动通常比普通振动模强 5 到 10 倍，从而显著增强了信号强度。 通过同时捕获斯托克斯和反斯托克斯信号，可以验证光谱特征，并利用信号对称性精确确定激发波长（0 cm⁻¹），从而无需对系统进行重新校准。
图1：台式太赫兹拉曼模块
THz-Raman Spectroscopy Modules are designed as integrated, ultra-compact, plug-and-play solutions to upgrade your existing Raman spectrometer. Comprising an ultra-narrowband ASE-free laser source, NoiseBlock™ 90/10 beamsplitter, and dual-stage SureBlock™ notch filters, the system delivers >OD9 Rayleigh attenuation and signal capture of both Stokes and anti-Stokes signals down to 5 cm-1. (Figure 1)
图2：卡马西平的太赫兹拉曼光谱清晰地显示了其多晶型和水合形式的差异。²
系统配置
All TR-Series THz-Raman modules are ultra-compact and simple to connect via fiber to almost any spectrometer or Raman system. A high-power, wavelength-stabilized, single-frequency laser source is precisely matched to the ultra narrow-band ASE, beamsplitter and notch filters to assure maximum throughput and exceptional attenuation (>OD 9) of the excitation source. Systems are available in 532 nm, 633 nm, 785 nm, and 808 nm excitation wavelengths.
The TR-PROBE is a compact, robust THz-Raman probe that enables in-situ reaction or process monitoring, and can also be flexibly configured with a variety of sample interface accessories, including immersion or contact probe tips, a convenient vial/tablet holder, a Transmission Raman adapter, a microscope mount, or a steerable non-contact optic (see options below). A separate CleanLine™ laser provides ASE-free excitation via a multimode fiber, enabling the probe to operate in harsher environments where electrical connections are not permitted. Options include circular polarization or a dual-port/dual polarization output for simultaneous measurement of both S and P polarizations.
The TR-BENCH is configured for benchtop use and offers a similar range of interchangeable sample interface accessories holder for fast, easy measurements. The system also comes with a standard cage mounting plate (centered on the collimated output beam) to allow for customized collection optics or easy integration into a customized system. Options include circular polarization or a dual-port/dual polarization output for simultaneous measurement of both S and P polarizations.
TR-MICRO可直接安装在多种主流显微镜平台和微拉曼系统上，并可轻松地将其接入或移出光路。线性偏振为标准配置，圆偏振为可选配置。
THz-Raman modules are compatible with virtually any commercial Raman system or spectrometer, and Coherent can recommend or integrate an appropriate spectrometer and deliver as a complete turnkey system.
A variety of sample interface accessories enable the TR-PROBE and TR-BENCH to be easily configured to match a broad range of applications. Immersion or contact probe tips may be mounted with either a fixed SwageLok mount, or for longer probes that may need alignment, an adjustable tip/tilt probe mount. The Vial/Tablet Sample Holder incorporates an adjustable steering mirror, interchangeable focusing lens, and safety shutter, and the Steerable Non-contact Optic Mount allows for projection and steering of the output beam with precision alignment and interchangeable focusing optics, for applications requiring long-range collection paths. New accessories include a Transmission Raman adapter (Probe only) which is ideal for bulk sampling of tablets or vials, and a Microscope mount with in/out optical switching and beam steering adjustments.
THz-Raman Applications Examples
晶体监测与分析 利用太赫兹拉曼光谱，对共晶体的识别与监测也得到了改进。上图显示了当咖啡因与2-苯甲酸的混合物中形成共晶体时，所发生的清晰可辨的峰位偏移。
在太赫兹拉曼波段，许多气体的旋转振动模式表现得十分明显。该波段的信号强度可达指纹波段的10倍，这为将拉曼光谱技术应用于超高灵敏度的气体检测开辟了可能性。此外，斯托克斯/反斯托克斯比值也可用于原位温度检测。
多晶型鉴定 在原料分析、成品检测、工艺监控和质量控制应用中，可轻松区分药物的多晶型和水合物。
相态监测 观察到硫从室温（α）加热至95.2°C（β），再加热至熔点115.21°C（λ）时的相变。请注意太赫兹拉曼波段中峰位、形状和强度的明显变化。晶体相会产生尖锐的峰，随着硫液化，这些峰逐渐变宽并消失。
Phase Monitoring Low frequency spectra can be used to monitor transformation of polymorphs. The waterfall plot above shows anhydrous theophylline before and after its transformation into a flocculated slurry, over a period of approximately 100 seconds. (data courtesy Clairet Scientific Ltd.)
合成路径分析：爆炸物法医鉴定 多份ETN（赤藓糖四硝酸酯）样本，代表了原料和制备途径的系统性变化，呈现出显著差异。
1 美国专利第7,986,407号和第8,184,285号。
2 Data taken using SureBlock™ notch filters and a single-stage spectrometer at 785 nm.
