THz-Raman® – The “Second Fingerprint” of Raman
Ondax’s patented1 THz-Raman® Spectroscopy Systems extend the range of traditional Raman spectroscopy into the terahertz/low-frequency regime, exploring the same range of energy transitions as terahertz spectroscopy – without limiting the ability to measure the fingerprint region. This region reveals a new “Structural Fingerprint” to complement the traditional “Chemical Fingerprint” of Raman, enabling simultaneous analysis of both molecular structure and chemical composition in one instrument for advanced materials characterization.
Features
• Fast collection of THz-Raman® spectra from 5cm-1 to >3000cm-1 (150GHz to 90THz)
• Simultaneous Stokes and anti-Stokes signals improve SNR while providing inherent calibration reference
• Available as add-on to an existing microscope or Raman system, or as a complete custom-configured system
• Simple optical in/out switch removes system from optical path when not in use
• Fiber coupling enables easy interface to a wide range of spectrometers
• Available at 532nm, 785nm, 850nm, 976nm and 1064nm excitation wavelengths
• Compatible with Leica, Zeiss, Nikon and Olympus microscopes
Applications
• Polymorph identification and analysis
• Trace detection and source attribution of explosives/hazmat/drugs
• Crystallization and reaction monitoring
• Structural studies of nano- and bio- materials, photovoltaics, and semiconductors
• Forensics, archeology, mineralogy
See What You’ve Been Missing – More Data, Better Sensitivity & Reliability
Clear real-time differentiation of structural attributes of the material enables clear identification and analysis of polymorphs, raw material sources, defects & contamination, crystal formation, phase monitoring and synthesis methods.
One Sample, One System, One Answer
Real-time, simultaneous measurement of both composition and structural analysis eliminates the need for multiple samples and instruments, lowering capital, training and maintenance costs.
Benefits
• Both chemical composition + molecular structure from one Raman measurement
• Real-time structural monitoring + chemical analysis
• Higher SNR with inherent calibration reference
• Faster, more comprehensive and reliable measurements
• Compact, easy to use, and adaptable to existing Raman systems
Full Raman spectrum of the pharmaceutical Carbamazepine showing both the THz-Raman “Structural Fingerprint” and traditional “Chemical Fingerprint” regions. Note higher intensity and symmetry of THz-Raman signals.
THz Raman: Covering low frequencies, anti-Stokes, plus the traditional fingerprint region!
THz-Raman® extends the reach of Raman systems into the low-frequency, (low wavenumber) spectral regime where important structural details can be discerned, including polymorphs, isomers, cocrystals, and lattice/phonon modes. The high optical density, ultra-narrowband, high-throughput design virtually eliminates the Rayleigh signal while enabling rapid collection of both Stokes and anti-Stokes signals from ± 5cm-1 to >3,000 cm-1.
The examples below show spectra in the ~5-200cm-1, or 150GHz-6THz regimes, using two different excitation wavelengths. For strong Raman scatterers such as Sulfur (left), the ratio of Rayleigh peak to signal peak is exceptionally low. The L-Cystine spectrum (right) shows how narrow the filters are by producing clearly differentiated signals down to <10cm-1. Both examples also demonstrate the simultaneous capture of symmetrical anti-Stokes signals, which can be used to confirm peak locations while providing an inherent calibration reference (the Rayleigh line is exactly between the symmetrical peaks).
The clean, distinct signals from the THz-Raman® systems provide clear differentiation between phases, crystals and polymorphs, capturing molecular structural information via their vibrational/phonon modes. Carbamazepine (left) exhibits clearly unique low-frequency spectra for all polymorphic forms. THz-Raman signals are typically much stronger than fingerprint signals, and are also affected by synthesis methods: various formulations of the home-made explosive ETN show distinct differences and can used in source attribution (right).
THz-Raman® System Specifications:
Parameter
Units
Specification
Wavelength1
nm
532
785/850
976
1064
Power at sample port (min)
mW
50 to 2502
100
300
200 to 4502
Physical Dimensions (W x L x H)
in
10” x 15” x 3.25”
1 Also available with fiber-coupled input for 488nm, 514nm, and 633nm
2 Specify power level at time of order
Spectrometer3:
Fixed Grating Spectrometer
Tunable Grating Spectrometer
Spectral Range (typical)
-200cm-1 to +2200cm-1
400-1100 nm (w/Si Detector)
Spectral Resolution
2.5cm-1 to 4cm-1
0.7cm-1 or greater
Computer Interface USB
USB
3 Spectrometer specifications depend on manufacturer and options ordered
System Description and Configurations:
All THz-Raman® Series platforms are ultra-compact and simple to connect via fiber to almost any spectrometer or Raman system. Our patented SureBlock™ ultra-narrow-band Volume Holographic Grating (VHG) filters precisely block only the Rayleigh excitation with >OD8 attenuation, enabling simultaneous capture of both Stokes and anti-Stokes signals. A high-power, wavelength-stabilized, ASE-free single-frequency laser source is precisely matched to the filters to assure maximum throughput and exceptional attenuation of the excitation source.
The TR-MICRO mounts directly to a broad range of popular microscope platforms and micro-Raman systems, and can be easily switched in and out of the optical path. The system includes an Ondax SureLock™ 785nm, 850nm, 976nm or 1064nm laser source, notch filters, and optional circular polarization (linear polarization is standard). A 532nm excitation source or a sample imaging camera are also available upon request.
The new TR-PROBE is a compact, robust THz-Raman® probe that enables in-situ reaction or process monitoring. The TR-PROBE can be configured with a variety of immersion or contact probe tips, a convenient vial holder, tablet holder, or a steerable collimated beam (see sample options on previous page).
The XLF-CLM and XLF-C are configured for Benchtop use and offers an optional vial/cuvette sample 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. The XLF-CLM includes a SureLock™ 785nm, 850nm, 976nm or 1064nm laser source, notch filters, and optional circular polarization. The XLF-C has a fiber-coupled input for DPSS and gas laser excitation wavelengths.