Handheld Raman Spectroscopy - For Art and Cultural Heritage Analysis

Importance of the Topic

Raman spectroscopy provides crucial non-invasive insights into the molecular and material composition of artworks and heritage objects. Its ability to probe pigments, binders, varnishes and inorganic components without sampling or damaging precious items makes it indispensable for conservation, authentication and cultural heritage research.

Objectives and Study Overview

This article introduces the BRAVO handheld Raman spectrometer developed by Bruker for on-site analysis of art and cultural artifacts. It aims to demonstrate how the instrument overcomes traditional limitations of portable Raman devices, particularly regarding fluorescence interference, sensitivity and spectral accuracy, while preserving sample integrity.

Methodology and Instrumentation Used

The BRAVO system combines two key technologies to achieve high performance in a compact format:

• DuoLaser™ excitation spanning the fingerprint and CH-stretching regions (170–3200 cm⁻¹) for broad spectral coverage.
• SSE™ (Shifted Excitation Raman Spectroscopy) to suppress fluorescence by acquiring sequentially shifted spectra and isolating the Raman signal.

Measurements can be conducted directly on artifacts without contact, using a laser power below 100 mW to minimize the risk of heating or alteration. A tripod mount and remote control via Wi-Fi or Ethernet facilitate stable, reproducible data collection.

Main Results and Discussion

Comparisons with benchtop FT-Raman show that BRAVO achieves similar spectral quality in challenging samples such as kaolin, even in the presence of strong fluorescence. The SSE™ approach effectively removes fluorescence backgrounds while maintaining unmatched wavenumber accuracy (±1 cm⁻¹). Advanced software features enable automated library searches against pigment and binder databases, accelerating compound identification in the field.

Benefits and Practical Applications

The BRAVO handheld spectrometer delivers:

• True non-destructive analysis ensuring preservation of valuable objects.
• High sensitivity across a wide spectral range without resorting to high-power lasers or cooled detectors.
• Portability for in-situ measurements on large or immovable works.
• Remote operation and tripod compatibility for stable long acquisitions.
• Integrated software for rapid spectral matching to art conservation libraries.

Future Trends and Possibilities

Looking ahead, the integration of expanded spectral libraries, machine-learning algorithms for automated interpretation and the combination of handheld Raman with complementary techniques (e.g. portable XRF, IR) will further enhance non-invasive heritage analysis. Continued development of fluorescence suppression and miniaturized detectors may push sensitivity even closer to laboratory systems.

Conclusion

The BRAVO handheld Raman spectrometer represents a significant advance in portable spectroscopy for art conservation. By merging DuoLaser™ excitation with SSE™ fluorescence mitigation, it achieves laboratory-grade performance in the field, enabling accurate, non-destructive identification of materials on valuable cultural artifacts.

Reference

• Conti et al. Analyst 141, 4599 (2016)
• Vagnini et al. Spectrochimica Acta Part A 176, 174 (2017)
• Bruker Product Note T29 12/15 on SSE™ fluorescence mitigation
• Bruker Product Note R34 05/16 on advanced data acquisition and evaluation