Imaging & Sensing
Laser sources for spectroscopy, non-destructive testing and machine vision
Many measurement and inspection techniques depend on a laser source with very specific properties: a narrow, stable spectral line, short high-energy pulses, or a well-defined light pattern. We design and manufacture these sources, from wavelength-stabilized diodes to pulsed solid-state lasers, for instrumentation manufacturers and integrators.
Raman spectroscopy
Raman spectroscopy identifies materials by their vibrational fingerprint, without contact and without sample preparation. The Raman signal is very weak, so the source must have a narrow, stable line, free of side modes or amplified spontaneous emission that could mask it [1]. Choosing the wavelength is a trade-off: the signal grows with the fourth power of the frequency, but shorter wavelengths excite more fluorescence in many samples [1].
| Wavelength | Typical use |
|---|---|
| 785 nm | Most widespread compromise between signal and fluorescence; silicon detectors |
| 830 nm | Less fluorescence than at 785 nm, with silicon detectors |
| 1064 nm | Minimal fluorescence for highly fluorescent samples; InGaAs detectors |
Our diode bars are wavelength-stabilized with volume Bragg gratings (VBG), which narrow the emission and lock it against changes in current and temperature. They deliver tens of watts per bar in continuous-wave operation, with a typical spectral width of ~0.2 nm, around 3 cm⁻¹ at 785 nm.
LIBS
Laser-induced breakdown spectroscopy (LIBS) analyzes the elemental composition of solids, liquids and gases. A nanosecond pulse is focused on the sample, generates a plasma, and its emission reveals the elements present. It is a fast, contactless technique that needs no sample preparation, suited to both laboratory and field use, with applications in metal alloys, mining, soils, cultural heritage, food and the environment [2]. The most widely used source is the Q-switched nanosecond Nd:YAG laser [2].
We manufacture high-energy Q-switched Nd:YAG lasers at 1064 nm, with nanosecond pulses and an optional second-harmonic module at 532 nm.
Non-destructive testing
Active thermography. A laser locally heats the part and an infrared camera records how the heat spreads: surface cracks interrupt the heat flow and show up in the image. Heating with a laser line scanned across the surface makes it possible to inspect large areas, and detectability improves with laser power [3]. We have supplied line emission modules with custom geometries for active thermography equipment.
Laser ultrasonics. A short laser pulse generates ultrasonic waves in the part through thermal expansion or ablation, and a second laser coupled to an interferometer detects them, without contact and with a typical bandwidth of 1–30 MHz [4]. It is used for damage detection, material characterization and cure monitoring of composites [4]. Our high-energy Q-switched Nd:YAG lasers are suitable as generation lasers. Research centers have also built generation lasers with our gain modules, and we have developed custom lasers based on them.
Illumination and pattern projection
Machine vision, 3D metrology by triangulation, profilometers and alignment systems need to project lines, crosses, dots or patterns with good definition. We manufacture low-power diode modules from 405 to 1550 nm, with continuous, switched or modulated emission, fixed, collimated or focusable optics, and custom patterns with very low line bowing. Thermoelectric wavelength stabilization is available on request.
Our sources
From VBG-stabilized diodes and pattern projection modules to gain modules and Q-switched Nd:YAG lasers, we supply the right source for each technique, either as a component for integration or as a custom laser.
References
1. Paschotta R. Lasers for Raman spectroscopy. RP Photonics Encyclopedia. https://www.rp-photonics.com/lasers_for_raman_spectroscopy.html
2. Shah SKH, Iqbal J, Ahmad P, et al. Laser induced breakdown spectroscopy methods and applications: a comprehensive review. Radiat Phys Chem. 2020;170:108666. doi:10.1016/j.radphyschem.2019.108666
3. Puthiyaveettil N, Thomas KR, Unnikrishnakurup S, et al. Laser line scanning thermography for surface breaking crack detection: modeling and experimental study. Infrared Phys Technol. 2020;104:103141. doi:10.1016/j.infrared.2019.103141
4. Zarei A, Pilla S. Laser ultrasonics for nondestructive testing of composite materials and structures: a review. Ultrasonics. 2024;136:107163. doi:10.1016/j.ultras.2023.107163
Developing a measurement or inspection instrument?
Tell us about the technique, the wavelength, the power or energy and the format you need, and we will work with you to define the most suitable configuration. We develop custom solutions for equipment manufacturers and integrators.
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