Choosing the right excitation wavelength is one of the most important decisions when investing in a Raman spectroscopy system. Two of the most widely used laser wavelengths are 785 nm (near-infrared) and 1064 nm (infrared). Each offers distinct advantages depending on your application and the nature of your samples.
Below, we explore the key differences, benefits, and ideal use cases for both technologies.
785 nm Raman Spectroscopy: The Versatile Workhorse
The 785 nm wavelength is one of the most commonly used in Raman instruments because it offers an excellent balance between signal strength and fluorescence suppression.
- Advantages:
- Stronger Raman signal compared to longer wavelengths
- Moderate reduction of fluorescence, better than 532/633 nm lasers
- Compatible with compact, lower-cost systems
- Uses CMOS/CCD detectors with high resolution and high sensitivity
- Ideal for routine analysis, organic compounds, biological materials, and pharmaceuticals
- Several kinds of hazadous materials or explosives can be identified
- Limitations:
- Still susceptible to fluorescence in highly fluorescent or dark-colored samples
- May not produce usable spectra for some pigments, polymers, or natural substances
1064 nm Raman Spectroscopy: The Slower Fluorescence Fighter
When fluorescence becomes a serious problem, 1064 nm systems are the solution, where another advances methods used in another system fail. While the Raman signal is inherently significantly weaker, the near-complete suppression of fluorescence often makes this the only viable choice for difficult samples.
- Advantages:
- Reduced fluorescence, even from highly problematic samples
- Ideal for dark, carbon-rich, or aged materials (e.g. inks, pigments, soils)
- Allows analysis of artworks, historical artifacts, forensics, and natural substances
- Minimizes laser-induced heating and sample damage
- Limitations:
- Weaker Raman signal, requiring longer integration times and special detectors (InGaAs) working far from visible spectral range
- Not suitable for measuring weak signals, low concentration solutions or traces of materails
- Systems are typically larger, heavy with high energy consumption and more expensive
- Lower spectral resolution compared to shorter wavelengths
Side-by-Side Comparison
| Feature | 785 nm | 1064 nm |
|---|---|---|
| Raman Signal Strength | High | Moderate to Low |
| Fluorescence Suppression | Medium | Very High |
| Detector Type | CMOS / CCD | InGaAs (usually cooled) |
| Sample Heating Risk | Moderate | Low |
| System Size & Cost | Compact, cost-effective | Larger, higher cost |
| Best For | Routine lab work, organics, pharma | Fluorescent samples, dark materials |
| Not Ideal For | Strongly fluorescent samples | Trace detection, fast screening |
Which Should You Choose?
Choose 785 nm if you need:
- High sensitivity, measurement of low concentrations, almost trace detection
- Faster measurements
- A cost-effective solutiuon
- general and multi purpose Raman device
Choose 1064 nm if you need:
- Clean spectra from fluorescent or usage for dark samples
- Non-destructive analysis of sensitive materials
- High chemical specificity with minimal interference
Conclusion
Both 785 nm and 1064 nm Raman spectroscopy offer powerful capabilities, but they serve different purposes. If your work involves materials with high fluorescence (especially pigments) or if you need suppres it, but your samples provides strong Raman response, 1064 nm can be better choice. For most other applications, 785 nm offers an ideal mix of performance and versatility.
Need help selecting the right Raman system? Contact our specialists for expert advice tailored to your samples and applications.