Laser Applications in Metrology

1. Introduction: The importance of lasers in measurement technology

Lasers have revolutionized measurement technology and enable precision at a level that is unattainable with conventional methods. Their properties such as high coherence, low divergence and a precisely adjustable wavelength make them indispensable. CW lasers and tunable lasers in particular are widely used in precision measurement technology.

A key advantage of lasers is their versatility. Applications such as interferometry use lasers for high-precision measurements of distances and angles. They play a key role in this, as they are indispensable for many industries.

In addition, laser safety glasses ensure safety when working with high-power laser systems. This is especially important in industrial environments where safe working conditions are a top priority.

Due to the continuous development of laser technology, new Laser Applications in Metrology possible, raising precision and efficiency to a new level.

2. Basics of laser technology for measurement technology applications

Structure and Function of a Laser

A laser (Light Amplification by Stimulated Emission of Radiation) produces light that is highly coherent, monochromatic and focused in a narrow beam. This is achieved by amplifying photons in an active medium that is excited by an energy source. The mirrors of the resonator are crucial for this, amplifying the light and directing it precisely.

Important parameters: wavelength, power and coherence

The wavelength of a laser determines which applications it is suitable for. For example, infrared lasers are often used in spectroscopy and materials analysis. The power of a laser, measured in watts, varies from milliwatts for laboratory applications to several kilowatts for industrial cutting applications.
Coherence is a crucial parameter in metrology because it enables the interference ability of light and thus supports applications such as interferometry.

laser classes and safety standards

Lasers are classified according to their level of danger, from Class 1 (not dangerous) to Class 4 (potentially dangerous to skin and eyes). Safety standards such as the use of laser safety glasses are essential, especially with high-power lasers, to protect users. Safe use is an essential part of all Laser Applications in Metrology, especially with high-power lasers.

3. Interferometry: Precise Laser Applications in Metrology

How an interferometer works

An interferometer uses the principle of light interference to measure distances, angles or surface profiles with extremely high precision. The system splits the laser light into two beams that travel different paths. It reunites the beams and creates interference patterns that reveal the measured quantity. Michelson interferometers in particular are known for their accuracy in precision measurement technology. Interferometers are one of the most important Laser Applications in Metrologybecause they deliver highly precise results.

Applications: Distance, angle and surface measurements

Interferometry is used in various areas of measurement technology:

• Distance measurement: Ideal for the precise determination of small distances, for example in semiconductor production.
• Angle measurement: In optical systems to make precise adjustments.
• Surface measurements: For the analysis of surface roughness or flatness, for example in the production of optical components.

For example, the combination of interferometers and powerful cw lasers enables particularly precise measurements in industry and research.

CW / quasi-CW laser

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Example: Twyman-Green interferometer: structure and areas of application

The Twyman-Green interferometer is a further development of the Michelson interferometer and is used specifically for testing optical components. Similar to the Michelson interferometer, a laser beam is split into two beams. One of the beams is directed at the object to be tested (e.g. a lens or a mirror), while the other serves as a reference beam. When the beams are recombined, an interference pattern is created that makes deviations in the shape or quality of the optical surface visible.

This interferometer is particularly useful in the manufacturing and quality control of optical systems because it can detect tiny defects and distortions. It is often used in conjunction with cw lasers, which are known for their high stability.

Advantages of the Twyman-Green interferometer

• High precision: Ideal for measuring the smallest surface deviations.
• Flexibility: Can be adapted for different optical components such as lenses or mirrors.
• Easy integration: Can be integrated into automated measuring systems, enabling efficient quality control.

4. Spectroscopy: Advanced laser measurement technology for molecular analyses

Raman Spectroscopy: Making Molecular Structures Visible

Raman spectroscopy is a widely used method for analyzing molecular structures. A laser beam is directed at a sample and the light scattered back is examined. The Raman shift - small frequency changes caused by the interaction of light with molecular vibrations - can be used to precisely identify chemical compositions and bonds.

This technique is particularly advantageous because it allows for minimally invasive analyses and requires minimal sample preparation. Tunable lasers are ideal for Raman spectroscopy because they can be flexibly adapted to different classes of molecules.

Near-infrared spectroscopy (NIR): Versatile applications

NIR spectroscopy analyses the absorption behaviour of materials in the near infrared range (800–2500 nm). This method is ideal for determining chemical and physical properties as it can penetrate deep into samples. It is often used in the food and agricultural industries, but also in pharmaceutical research, e.g. for moisture determination or for the analysis of complex mixtures.

Pulsed lasers can be used in NIR spectroscopy to improve sensitivity and measurement speed, especially in the analysis of volatile substances.

CARS (Coherent Anti-Stokes Raman Spectroscopy): Advanced Raman technology

CARS is an extension of Raman spectroscopy, which uses coherent light to amplify chemical signals. This technique enables rapid and highly sensitive analysis of molecules and is used in biology and materials research, for example. Due to the use of pulsed lasers, dynamic processes can also be observed in real time.

LIBS (Laser-Induced Breakdown Spectroscopy): Elemental analysis by laser

The LIBS technique uses a pulsed laser to ionize the surface of a sample. The resulting plasma emits light, the spectrum of which reveals the chemical composition of the sample. LIBS is a fast and non-destructive method that is particularly valued in environmental analysis and material testing. This is why the technology represents one of the most innovative Laser Applications in Metrologybecause it works non-destructively and efficiently.

5. Laser triangulation: An indispensable laser application in measurement technology

principle of laser triangulation

Laser triangulation is a precise method of measuring distance in which a laser beam is projected onto a surface and the reflected light is detected by a detector. By evaluating the angle between the laser source, reflected light and detector, the distance can be calculated. This technique is particularly effective for measurements on irregular or moving surfaces.

The high accuracy and speed make laser triangulation ideal for applications in industrial manufacturing and quality control. Compact cw lasers are used here, which impress with their high stability and long service life.

Applications in industrial quality assurance

Laser triangulation is often used in quality assurance to check dimensions, surface profiles or edge positions. Examples of applications include:

• Component measurement: Precise measurement of length, width and height of workpieces.
• defect detection: Identification of surface defects such as dents or cracks.
• Process monitoring: Real-time control in production lines to ensure dimensional accuracy.

The ability to capture measurement data quickly and without contact makes this technology particularly efficient and economical. Laser beam guidance components are often used to optimally adjust the light guidance.

Advantages: Speed and accuracy

Laser triangulation offers numerous advantages over conventional measurement techniques, such as:

• High measuring speed: Ideal for real-time applications in manufacturing processes.
• Excellent accuracy: Even the smallest deviations can be detected, which increases the quality of the products.
• Non-contact measurement: Particularly suitable for sensitive or moving surfaces.

These properties make laser triangulation indispensable for modern production environments. It is one of the most efficient and flexible Laser Applications in MetrologyIn combination with a power meter, the laser power can be monitored to ensure, for example, optimal measurement results.

power meter

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6. Laser scanner: 3D measurement technology and other laser applications

Structure and Function of a Laser Scanner

A laser scanner uses precisely controlled laser beams to capture objects in three dimensions. The laser beam scans the surface of an object while sensors record the reflected light signals. The captured data is converted into a detailed 3D model that is used for analysis, design optimization or manufacturing processes.

Their ability to scan large objects quickly and accurately makes laser scanners essential in industries such as architecture, engineering and manufacturing. Modern devices such as the Nanocam also offer ultra-high resolution for nanometer-precise scanning.

The Nanocam: Precision at the Nano Level

The Nanocam from 4D Technology sets new standards in 3D measurement technology. With its ability to capture surfaces with a resolution in the nanometer range, it is ideal for the inspection and analysis of the finest structures. This laser scanner technology finds applications in the semiconductor industry, materials research and the production of high-precision components.

A key advantage of the Nanocam is its ease of use and compactness. Due to the integration of the latest laser technology, it delivers highly precise data that can optimize production processes and minimize errors. This product shows how precise and advanced modern Laser Applications in Metrology can be.

Applications in 3D measurement technology

Laser scanners like the Nanocam are used in a variety of applications:

• Quality control: Precise measurement of components to ensure dimensional accuracy and surface quality.
• Research and Development: Creation of detailed 3D models for material studies and prototype development.
• Reverse Engineering: Reconstruction of existing objects for adaptations or re-production.

Thanks to their versatility and precision, laser scanners make an important contribution to increasing efficiency and product quality in modern manufacturing. Products such as the Nanocam set new standards in 3D measurement technology and offer companies decisive competitive advantages. (More information on the NanoCam: https://4dtechnology.com/products/optical-profilers/nanocam-hd/)

7. Innovative Technologies: The Future of Laser Applications in Metrology

Femtosecond laser: precision in the nanometer range

Femtosecond lasers are among the most modern technologies in measurement technology. These lasers emit ultra-short light pulses that last only a few femtoseconds (1 femtosecond = 10⁻¹⁵ seconds). This enables extremely precise measurements and material processing to be carried out without causing thermal damage.

Applications of femtosecond lasers include:

• Materials research: Analysis and processing of sensitive materials such as glass or biological samples.
• Micromachining: Engraving and cutting with the highest precision.
• Nonlinear spectroscopy: Investigation of molecular structures using highly sensitive measuring methods.

Femtosecond lasers are increasingly used in science and industry, especially in areas where the highest precision is required.

Optical Coherence Tomography (OCT): Medicine and Materials Testing

Optical coherence tomography (OCT) uses coherent light to create high-resolution cross-sectional images of materials or biological tissues. This technique is widely used in medicine, e.g. in ophthalmology to analyze the retina, but also in material testing to examine layer structures.

With its ability to measure non-destructively and in real time, OCT offers enormous added value for industrial and scientific applications. Laser beam guidance components play a central role in precisely directing the light beams.

Nonlinear optical effects: New possibilities for measurements

Nonlinear optical effects open up new possibilities in measurement technology. These effects occur when laser light with high intensity interacts with special materials. Examples include:

• Harmonic generation: Doubling or tripling the frequency of light to extend the measuring range.
• Self-focus: Increasing the light intensity in a medium for specific measurement applications.

Such effects are increasingly used in materials research and spectroscopy, for example in combination with modern laser systems such as tunable or pulsed lasers.

8. Selection and Calibration: Optimal Lasers for Metrology Applications

What to look for when choosing a laser

The choice of the right laser measuring device depends largely on the intended application. Decisive parameters are:

• Wavelength: Different materials and applications require specific laser wavelengths (e.g. infrared for materials research, visible light for optical applications).
• Operating mode: CW lasers are ideal for continuous applications such as interferometry, while pulsed lasers are suitable for dynamic processes such as LIBS spectroscopy.
• Performance and stability: Precision applications require powerful and stable lasers that deliver consistently reproducible results

Calibration and maintenance: ensuring long-term precision

Regular calibration of laser measuring devices is essential to ensure precise and reliable results. This includes checking the laser wavelength, beam intensity and alignment of optical components. Calibration steps can be:

• Comparison with certified standards to ensure accuracy.
• Adjusting the laser beam guide to ensure optimal focusing.
• Checking the optical components to detect contamination or wear.

Proper maintenance not only increases the lifespan of the equipment, but also increases efficiency in use. Laser safety goggles and other safety devices should also be checked regularly.

certifications and quality standards

When purchasing a laser measuring device, make sure that it complies with the relevant international standards, such as:

• ISO 9001: Quality management systems for equipment and processes.
• IEC 60825: Safety of laser products.
• ISO/IEC 17025: Requirements for the competence of calibration and testing laboratories.

Certified devices not only ensure safety, but also the reliability of the measurement results. This is particularly important in industries such as medical technology and semiconductor production.

9. Benefits of laser applications for your business

Increasing efficiency through precise measurement technology

Laser-based measurement technologies enable highly precise and reliable measurements that conventional methods often cannot achieve. This accuracy leads to shorter lead times, less rework and overall more efficient production. For example, cw lasers or tunable lasers can be integrated into automated manufacturing processes to deliver continuously precise results.

Companies benefit not only from the improved quality of their products, but also from the increased speed and flexibility that laser-based systems offer.

Cost reduction through durable and low-maintenance systems

Laser-based measurement technologies are known for their durability and low maintenance requirements. Modern laser systems, such as pulsed lasers or interferometers, are designed to operate reliably even under demanding conditions. This significantly reduces operating costs as less frequent maintenance cycles and spare parts are required.

In addition, the non-contact nature and high measurement speed of lasers minimize production downtime and material loss, which can result in significant savings in the long term.

Competitive advantages through innovative technologies

The integration of modern laser technologies into measurement technology gives companies a decisive advantage over their competitors. Precise and innovative applications such as spectroscopy (e.g. Raman or NIR spectroscopy) or interferometry make it possible to open up new markets and set higher quality standards.

Products like the Nanocam or power meters provide companies with tools that enable them to meet even the most demanding customer requirements. By using such technologies, companies can not only optimize their production, but also strengthen their brand image as technological pioneers.

10. Conclusion and further resources

Summary: Key findings

Laser Applications in Metrology have revolutionized the way precision and efficiency are achieved in industry, research and development. From interferometry to spectroscopy to laser triangulation, laser-based systems offer unparalleled accuracy, speed and versatility.
By using products such as cw lasers, tunable lasers, interferometers or high-precision laser scanners such as the Nanocam Companies can not only increase their productivity but also open up new markets.

Further resources

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