FT-Raman Spectrometer with 1064 nm Excitation

What is the FT-Raman Spectrometer with 1064 nm Excitation?

An FT-Raman spectrometer uses a 1064 nm Nd:YAG laser and an interferometer with InGaAs or germanium detector to record Raman spectra without fluorescence from most colored, biological and polymeric samples. It is chosen when dispersive Raman at 532 or 785 nm is swamped by fluorescence.

Overview

In FT-Raman, a 1064 nm Nd:YAG laser excites the sample at energies below most electronic transitions, which eliminates fluorescence in the majority of materials. The scattered light passes through a Rayleigh filter into a Michelson interferometer and is detected by a liquid-nitrogen-cooled germanium or room-temperature InGaAs detector. Spectral resolution of 2–4 cm-1 is typical, with a range from 50 to 3600 cm-1 and excellent wavenumber accuracy from the laser reference. Because Raman intensity scales as 1/λ4, signal is about 15 times weaker than at 532 nm, so laser powers up to 1–2 W and longer acquisition times of 1–10 minutes are used. Sample heating of dark samples can be an issue. FT-Raman is complementary to FTIR and is often integrated in the same platform with a Raman module, widely used for polymers, dyes, natural products and historical artifacts.

How does it work?

When monochromatic laser light hits a sample, most photons scatter elastically, but about one in 10 million scatters inelastically with an energy shift equal to a vibrational energy of the molecule. This Raman shift, reported in cm-1, produces a spectrum of peaks characteristic of chemical bonds and crystal structure. A Raman spectrometer consists of a laser such as 532, 633, 785 or 1064 nm, focusing and collection optics, a notch or edge filter that rejects Rayleigh scattering, a dispersive spectrograph with CCD detector or an FT interferometer, and software. Shorter laser wavelengths give stronger signals but can excite fluorescence, while 785 and 1064 nm reduce fluorescence at lower signal. Polarization, confocal pinholes and surface enhancement increase selectivity and sensitivity, and calibration with standards such as silicon at 520.7 cm-1 and acetaminophen ensures accurate shifts.

What are the key features?

• 1064 nm excitation eliminates fluorescence from most colored and biological samples.
• Interferometer provides wavenumber accuracy set by the laser reference.
• InGaAs or germanium detector options balance cost and sensitivity.
• Laser power up to 2 W with protective shutters and interlocks.
• Sample compartments for vials, solids, films and 180° backscatter.
• Can share a platform with FTIR to combine complementary spectra.

What are the technical specifications?

A typical ft-raman spectrometer with 1064 nm excitation configuration offers laser wavelength of 1064 nm (Nd:YAG), laser power of Up to 2 W (adjustable), spectral range of 50–3600 cm-1, spectral resolution of 2–4 cm-1 (optional 1 cm-1), wavenumber accuracy of ≤0.05 cm-1 and detector of InGaAs (RT) or Ge (LN2). Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The FT-Raman Spectrometer with 1064 nm Excitation is used in fluorescent polymer and dye analysis, natural products and botanical materials, historical artifact and pigment studies, pharmaceutical excipients and colored formulations and biological and food samples. Across the wider Raman class, laboratories also deploy it for pharmaceutical raw material identification, polymorph and API form analysis and carbon nanomaterials and graphene characterization.

Which standards and certifications apply?

Relevant standards and methods include ASTM E1840, ASTM E2529, ASTM E2911, USP <1120>, Ph. Eur. 2.2.48, IEC 60825-1 and ISO 17025. Certification candidates for this model are CE, IEC 60825-1 Class 1 and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Operate Raman systems in rooms with controlled ambient light or use an enclosed sample compartment, since stray light raises the baseline. Treat lasers according to IEC 60825-1 classifications and use interlocks and protective eyewear where open beams are possible. Check wavenumber calibration daily with silicon and intensity response with a standard material, and track laser power drift. Avoid burning dark or absorbing samples by reducing power and using rastering or defocusing. Cooled CCD detectors need stable temperature, and dust should be kept off optics. Maintain spectral libraries and validate identification methods against known references, especially for regulated raw material identification.

How do I select the right FT-Raman Spectrometer with 1064 nm Excitation?

Select FT-Raman when fluorescence prevents dispersive Raman measurement and acquisition time of minutes is acceptable. It has lower sensitivity and no microscopy unless an accessory is added. In an RFQ, specify laser power, detector, resolution, sampling accessories, FTIR integration and laser safety features.

How does it compare with other Raman variants?

Choose a Raman spectrometer based on the sample's fluorescence behavior, spatial scale and operating environment. Laser wavelength is the first decision: 532 nm for strong signal from inorganics and carbon, 785 nm for general organics and pharmaceuticals, and 1064 nm for highly fluorescent or colored samples. Bulk identification can use a benchtop or handheld instrument, while samples smaller than 100 µm or requiring depth profiling and mapping need a confocal Raman microscope. Process monitoring requires a fiber-optic probe and a robust enclosure. Compare spectral resolution of 2–6 cm-1, spectral range, laser power, detector cooling and library options. Consider laser safety class, sample heating risk and compliance with 21 CFR Part 11 in regulated laboratories.