Advanced Solutions for Optical Measurements

EXTENDING RAMANINTO THE THz REGIMEDELIVERING BOTH CHEMICAL COMPOSITION AND STRUCTURALINFORMATION IN A SINGLE MEASUREMENT

Carbamazepine

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Structural Fingerprint

ChemicalFingerprint

Both Stokes and anti-Stokes signalsfrom ± 5cm-1 to 200cm-1

(150GHz – 6 THz) – and beyond!

Complete chemicalfingerprint

Polymorphs and other structural attributes can be clearly identified by strong, low-frequency/THz-Raman signals

200 cm-1 to 2,000 cm-1± 5 cm-1 to 200 cm-1

Fig. 3 SureBlock™ wavelength selectivity at 785nm compared to a thin-film edge filter shows 10x improvement in resolution

Fig. 1 Benchtop THz-Raman module

SIMULTANEOUS MEASUREMENT OF BOTH CHEMICALAND STRUCTURAL PROPERTIESOndax 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.

Ondax 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, NoiseBlockTM 90/10 beamsplitter, and dual-stage SureBlockTM notch filters, the system delivers >OD9 Rayleigh attenuation and signal capture of both Stokes and anti-Stokes signals down to 5cm-1. (Fig 2)

The THz-Raman region (±5cm-1 to 200cm-1) corresponds to the THz-energy vibrations (150GHz-6THz) of inter-molecular/intra-molecular vibrations, including phonon modes, lattice modes, and/ rotational modes. These are often 5-10 times stronger than normal vibrational modes, significantly boosting signal strength. By capturing both Stokes and anti-Stokes signals, spectral features can be validated and the excitation wavelength (0cm-1) can be precisely determined due to signal symmetry, eliminating the need for system re-calibration.

Fig. 2 THz-Raman spectra of Carbamazepine shows clearly differentiated polymorphic and hydrated forms²

Ultra-narrow-band Notch Filters & Filter SystemsOndax patented¹ SureBlock™ ultra narrow-band notch filters are the enabling technology for highly selective wavelength applications like low frequency THz-Raman spectroscopy. With laser line attenuation of up to 99.9999% (optical density: OD 6) and a transition width of ~5 cm-1, SureBlockTM filters are more than 10 times narrower than available thin-film notch filters. High transmittance on both sides of the notch enables both Stokes and anti-Stokes Raman spectra to be simultaneously observed. Designed to fit into standard 1” optical mounts or incorporated into any XLF or TR Series THz-Raman® platform, SureBlock™ notch filters never degrade and are designed for high efficiency and excellent transmission. Available in standard wavelengths of 488nm, 532nm, 633nm, 785nm, 850nm, 976nm and 1064nm, Custom wavelengths available upon request.1 US Patents 7,986,407 and 8,184,2852 Data taken using Ondax SureBlock™ notch filters and a single-stage spectrometer at 785 nm

Key applications include:

> Differentiation and screening of polymorphs> Monitoring and quantifying degree of crystallinity> Characterizing and observing co-crystal formation> Process monitoring and analysis of chemical reactions> Characterizing thickness and orientation of few-layer nanomaterials> Structural characterization of polymers> Explosives detection and analysis, including determination of formulation methods> Advanced forensic analysis of materials

Excitation (Rayleigh) Linestructural

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anti-Stokes Raman Shift Stokes

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ASE SuppressionFilters

InterchangeableSample Interface

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WavelengthStabilized Laser

Fig. 2

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 532nm, 633nm, 785nm, 850nm, 976nm and 1064nm excitation wavelengths.

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. Linear polarization is standard, circular polarization is optional.

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 sample interface accessories, including immersion or contact probe tips, a convenient vial/tablet holder, 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.

The TR-BENCH is configured for benchtop use and offers the same 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.

Ondax THz-Raman® modules are compatible with virtually any commercial Raman system or spectrometer, and Ondax 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. Additionally, the accessories may be rotated around the dovetail mount to accomplish any angle of incidence.

TR-MICRO

Camera

Spectrometer

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Probe with Vial/Tablet Holder

Probe with Non-Contact Optic

Probe with Contact/ImmersionProbe Tip

Probe withoutaccessory –Collimated beam outputVial/Tablet Holder Adjustable Probe Mount Fixed Probe MountNon-Contact Optic

SYSTEM CONFIGURATIONS

Advanced Solutions for Optical Measurements

The NoiseBlockTM ASE (Amplified Spontaneous Emission) filters and CleanLineTM filter assemblies transmit ASE emission and reflect only the desired single frequency line, suppressing the broadband ASE spectral background of a single frequency laser by >40dB resulting in a clean, ASE-free beam (Fig. 1). NoiseBlockTM filters ensure the pure spectral excitation beam required for ultra-low frequency THz-Raman® spectroscopy and other demanding applications. They are designed to match the ultra-narrow spectral profile of our SureBlock™ Notch Filters, and are incorporated into all Ondax TR Series THz-Raman® Systems. They can also be used as spectrally selective 90/10 Beamsplitters, providing up to a 4x throughput improvement in Raman spectroscopy applications. Available from 400nm to 2000+nm, in free-space, fiber-coupled, and pre-assembled CleanLineTM configurations.

ASE Filters and Beamsplitters

Wavelengthstabilized laser

ASE VHG Filter

ASE filtered laser beam

TransmittedASE light

Specularreflection

Mirror or 2ndASE VHG Filter

Fig. 1

Integrated LM Module andCleanLine™ ASE Filter assembly

Free space ASE and 90/10 Beamsplitter orstandalone CleanLine™ ASE Filter Assembly

Raw laser diodes produce ASE light on the order of 40-60dB below the laser line that can affect critical measurements within 400-500cm-1 of the laser line. NoiseBlockTM filters efficiently suppress ASE, leaving a spectrally pure source for measurements down to <10cm -1. Typical performance is shown at right for a 405nm and 785nm lasers.

The majority of modern Raman spectroscopy systems depend upon wavelength stabilized diode laser technology pioneered by Ondax. The Ondax PowerLocker®, a miniature, ultra-narrowband Volume Holographic Grating (VHG) filter, creates an external cavity that “locks” the diodelaser wavelength into a narrowed optical spectrum. This increases spectral brightness and delivers the stabilized optical performance required for precise, repeatable Raman measurements.

All SureLock™ Wavelength Stabilized Laser Diodes and Laser Modules incorporate the PowerLocker® and are engineered for optimum Raman performance. Available in a wide range of wavelengths, power levels, and form factors, Ondax can also custom-configure a wavelength-stabilized solution to meet your exact application or OEM requirements for any Raman spectroscopy system.

WAVELENGTH STABILIZED DIODE LASERS

BENCHTOP

OEM SOLUTIONS COMPONENTS

TURNKEY MODULES

WAVELENGTHSTABILIZED LASERS405NM TO 1064NM

Crystal Monitoring and AnalysisIdentifying and monitoring the formation of cocrystals is also improved using THz-Raman spectra. The figure above shows the clearly recognizable peak shifts that occur when cocrystals are formed in a mixture of Caffeine and 2-Benzoic acid.

Phase MonitoringPhase changes of Sulfur observed when heated from room temp.(α) to 95.2°C (β) and then to the melting point of 115.21°C (λ). Note the clearly recognizable changes in peak location, shape and magnitude in the THz-Raman® region. Crystalline phases result in sharp peaks, which broaden and dissipate as the sulfur liquifies.

Gas SensingRotational modes of many gases can be clearly seen in the THz-Raman region. Signal intensities can be up to 10x those in the fingerprint region, opening up the possibility of using Raman for extremely sensitive gas sensing applications. The Stokes/anti- Stokes ratios can also be used for in situ sensing of temperature.

Phase MonitoringLow 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.

Polymorph IdentificationPolymorphic forms and hydrates of pharmaceuticals can easily be distinguished in raw materials analysis, finished goods, process monitoring, and QC applications.

Synthetic Pathway Analysis - Explosives ForensicsMultiple samples of ETN (Erythritol Tetranitrate), representing systematic variations of ingredients and preparation routes, show distinctive differences.

ADDITIONALAPPLICATIONS

Visit the Ondax Online Store to find off-the-shelf samples of hundreds of products, available forimmediate delivery.

For more information about Ondax products and the name of a local representative or distributor, visit www.ondax.com, email sales@ondax.com, or call 626.357.9600

For more information about Ondax products and the name of a local representative or distributor, visit www.ondax.com, email sales@ondax.com, or call 626.357.9600

No responsibility is assumed by Ondax, Inc. for use of this product nor for any infringements of patents and trademarks or other rights of third parties resulting from its use. No license is granted under any patents, patent rights or trademarks of Ondax, Inc., and the company reserves the right to make changes in specifications at any time without notice. Each purchased laser is provided with test data. Please refer to this data before using the laser.

© 2017 Ondax, Inc.

850 E. Duarte Rd. Monrovia, CA 91016626.357.9600 (Tel)626.513.7494 (Sales Fax)

Visit the Ondax Online Store to find off-the-shelf samples of hundreds of products, available forimmediate delivery.

ADDITIONAL APPLICATIONS

Pharmaceutical ApplicationsKey challenges for the pharmaceutical industry includes polymorph identification, reaction monitoring, raw material quality control, and counterfeit detection. THz-Raman® reveals “structural fingerprints” that can rapidly differentiate polymorphs, isomers, co-crystal, and other structural variations of substances and compounds.

Semiconductor and NanomaterialsGraphene and carbon nanotubes are just two of the many nanomaterials that exhibit strong low-frequency signals. For Graphene, THz-Raman® analysis can determine the number of monolayers, and for carbon nanotubes, the diameter of the structure. Differences in structural characteristics and defects in crystals can also be detected.

Industrial and PetrochemicalTHz-Raman® delivers additional sensitivity and information about molecular structure to control processes, improve yields, and monitor crystallization or structural transformation during manufacturing.

Gas SensingRotational modes of gases such as Oxygen provide signal intensities up to 10x those in the fingerprint region. Stokes/anti-Stokes ratios can also be used for remote sensing of temperatures in gases, plasmas, liquids and solids.

Crystallization and Reaction MonitoringLow-frequency THz-Raman® signals undergo clear, rapid shifts corresponding to changes in molecular structure, enabling highly sensitive, real-time monitoring of crystal form, phase, or structural transformations.

Explosives Detection, Forensics and Source AttributionTHz-Raman® goes beyond chemical detection to reveal a “structural fingerprint” that can be attributed to specific ingredients, methods of manufacture, and storage/handling of many popular home-made explosive (HME) materials, revealing clues about how and where they were formulated.