Explore Laser Measurement and Beam Analysis Insights

As part of a series of blog posts on future trends, Ophir, an MKS company, has raised awareness of an alarming concern – the worldwide shortage of semiconductor chips. These chips are used everywhere – from phones, laptops, and PCs – through to vehicles, washing machines, ATMs, and more.

Let’s find out how this shortage came about, what effects it is having on our world, and see how key players are stepping in to resolve it.

Like many of today’s issues, the trigger behind the semiconductor shortage was the COVID-19 pandemic.

During the pandemic, demand for laptops and computers surged. But this shortage didn’t just affect the production of personal computers, it also had a knock-on effect on other industries.

For example, a new car build typically contains up to 1500 different semiconductor chips. Delivery lead times for chips have gone from an average of 9 weeks, to a staggering 22 weeks.

The result? Delays in the production of over 1 million vehicles in North America alone, with worldwide manufacturers projected to lose about 210 billion dollars in sales.

In China, chip supply chain disruptions caused electricity shortages, leading the government to introduce rationing, ordering factories to work less hours per day. And yes, this has caused Chinese chip manufacturers to reduce their production, creating a catch-22 situation, where the chip shortage is getting harder to resolve.

With these issues creating havoc worldwide, key players have stepped in to assist. Among them - Intel has invested 20 billion dollars in two huge new semiconductor fabrication plants in Arizona.

Samsung Electronics has planned to triple their production capacity by 2026. And TSMC, the largest contract chipmaker in the world, have joined forces with Sony to invest 7 billion dollars in creating a factory in Japan.

Other companies are also ramping up production – SK Hynix, Micron Technology, Bosch, and Hyundai. You can read more about their efforts in the original blog post.

As key suppliers of semiconductor components, MKS also has an important role to play – and is well positioned to support these ongoing industry-wide efforts to increase production.

It’s our hope that with a joint effort, these companies will be able to mitigate the supply chain disruptions that we see today, and get semiconductor production back on track.

“If you can’t measure it, you can’t improve it”. Those are the words first spoken by William Thomson, a 19th century British physicist, also known as Lord Kelvin.

When it comes to improving laser-based processes, in the field of materials processing – these words certainly ring true.

Let’s explore Ophir’s article and find out how, and when, these measurements must absolutely, positively be made.

The way the laser light is applied to the material being processed is measured as a function of power density, or energy density. If the laser power or beam size change over time, the new power density will affect the way the laser light is applied to the material – causing unexpected results. This makes it extremely important to collect and apply laser measurement data at certain times in a laser’s lifecycle, to ensure the process is consistent.

The article lists five stages when laser measurement is essential.

One - during application development – as the precise implementation of key performance parameters will determine the productivity of the laser system.

Two - when the laser source is integrated in the system – at this point, the parameters of the developed application are usually transferred to a very similar laser for use in the actual system, so measurements should be retaken and compared, to ensure they remain the same.

Three - during system runoff, delivery and movement – before the system is accepted by the customer, to ensure it meets the required criteria.

Four – periodically during productive use, as components may degrade over time, and debris can collect, affecting performance.

And finally, five – for preventative and corrective maintenance – a comprehensive maintenance routine protects the laser. Measurements before and after the maintenance can validate the system’s performance.

Read the article to find out more about each of these stages.

Another important factor is the repeatability of the measurements – they must be reliable, and easy to perform, to ensure consistent results. One tool suited to this task is Ophir’s BeamWatch laser beam profiler – as it provides real-time, non-contact measurements, and is very simple to set up. Follow the link in the article for more information.

There’s no question that materials processing demands reliable and frequent laser measurements – throughout the laser’s lifetime – and luckily, Ophir offers tools to suit every system.

Since the beginning of time, man had busied itself with creating light sources. Let’s travel through time using Ophir’s article to explore the man-made light sources of the past, present, and future.

The earliest light sources were of course fire-based. The humble fire served as a light source, but also provided heat for cooking and warmth. Then, candles and oil lamps allowed fire to be controlled just for the purpose of providing light.

Moving on to the beginning of the 19th century, gas lanterns appeared in the streets of major European and American cities.

At the end of the 19th century, the incandescent light bulb made its first appearance – the rise of the electric light. 140 years later, we still use these bulbs. However, there are some problems – with electric current transmitting through a highly-resistant filament, only a very small portion of electrical energy is made into light – the rest is lost as unwanted heat. Also, much of the radiation produced is invisible, limiting the bulb’s luminous efficacy to 17 lumen/Watt.

So, what was next? Along came neon and fluorescent lights – using atomic transitions in gas tubes, triggered by electric discharge – leading to more durable and more energy-efficient light sources, with the ability to create bright white light. The downside? These light sources are fragile, and can contain hazardous elements. Their light also appears less natural due to spikes in their emission spectra.

Most recently, LED light sources have taken the forefront. Light Emitting Diodes are semiconductor light sources. In the 1960s, LEDs could only emit infrared, and then red, light – they were mainly used as indicators for electronic devices. It took more than 30 years to develop an LED light source that could be used for general purpose lighting – read the article to find out exactly how this was done.

The incandescent light bulb is expected to become history, thanks to LEDs, with their high luminous efficacy of 300 lumen/Watt and far longer lifetimes.

Are they perfect? Unfortunately not. There are concerns that the UV component of white light LEDs may be damaging to eyes and skin. And while the LED’s emission spectrum is smoother than that of neon or fluorescent lighting, and so its light looks more natural, it isn’t as smooth as the light generated by an incandescent light bulb. Constant research and development aims to improve LEDs even more, and we’re excited to see that happen.

Interested in hearing more? Read the full article.

Lasers are used in so many ways, from optical fiber internet to performing sophisticated medical procedures. But they’re also superstars in another field – measurements. Let’s explore Ophir’s article on lasers as measurement tools.

Laser-assisted measurements can enhance and improve the way physical quantities are measured. They can calculate the distance between objects, using different methods depending on the size of the object, it’s distance from the measurement device, and the required resolution.

For example, there’s LiDAR – which encompasses a range of techniques for generating 3D maps of the environment, based on projecting laser light and detecting the reflected signal. It’s often used for autonomous vehicle navigation, to determine the best and safest driving strategy.

Lasers have been useful in other fields of measurement – such as interferometry, spectroscopy, microscopy, and atomic clocks.

Interferometry relies on superimposing electromagnetic radiation that has traversed different optical paths, and extracting information from the resulting interference pattern. The world’s most advanced interferometer stands in the heart of the Laser Interferometer Gravitational-Wave Observatory experiment. It can detect gravitational waves due to the change they exert on a laser beam that travels in one of its four-kilometer-long interferometer arms, measuring changes in optical path of less than one ten thousandth of the size of a proton! Read the article to find out more.

Spectroscopy is the study of interaction between light and matter – a laser with a well-defined wavelength can be used to investigate energy gaps between two electronic states of atoms or molecules. This technology has allowed scientists to catalog atomic and molecular transitions of almost every element and molecule known to us.

Microscopy is the use of microscopes to magnify objects. At first, microscopes used only lenses to view the object with visible light, and their maximum resolution was limited by diffraction due to the wave nature of light. But super-resolution microscopes, using lasers, have found ways to surpass the diffraction limit, with incredible results.

Lastly – lasers play a key role in atomic clocks – the most precise time-measurement system device built by man. Atomic clocks use the known energy-level differences of certain atoms to generate a highly stable and repeatable signal, with a known frequency - from which time can be measured. Read the article to find out more about the laser’s involvement in this fascinating application.

All in all, lasers have contributed greatly to developing measurement tools that go above and beyond the capabilities of other measurement technologies.

The wavelength of a laser is one of its fundamental characteristics. Laser diodes, one of the most common laser sources, have wavelengths determined by their design and the materials they are made from. But what happens when you need a specific wavelength for your application, and the laser can’t generate it? That’s where laser wavelength conversion is used. Let’s take a look at Ophir’s article and find out how this is done.

First, let’s talk about tuneable lasers. Some lasers can be tuned, although the tuning range is limited by the gain medium bandwidth. The tuning is done by controlling loss in the laser cavity so it’s minimized for the wavelength at which lasing occurs. Tuning mechanisms can include controlling the laser’s temperature, or using microelectromechanical actuators to change the cavity’s length.

Most solid state lasers are not tuneable, as they have a narrow gain spectrum. One exception is the Ti-Sapphire laser which has a wide gain bandwidth and can be tuned between 650-1100 nanometers.

Linear wavelength conversion involves using the laser to pump a gain medium, such as a crystal, to a higher energy state – and the excited electrons then decay to a lower energy state by emitting radiation at a longer wavelength. Put the gain medium in a cavity, and a laser is formed. An example is the Nd-YAG laser, which is pumped by a laser diode at 808 nanometers and emits radiation at 1064 nanometers.

Next, we have nonlinear wavelength conversion, such as second-harmonic generation (SHG). A well-known example is the green laser that that uses a nonlinear crystal to convert 1064 nanometers to 532 nanometers. There are many requirements involved in this type of conversion, such as meeting phase matching conditions – read the article to find out more.

Lastly, we have non-coherent laser-driven light sources. One example is the generation of plasma that emits extreme ultraviolet radiation at a wavelength of 13 nanometers. This plasma is generated by focusing a high power CO2 laser, with a wavelength of about 10 micrometers, onto tin droplets in a vacuum – resulting in EUV light that enables advanced photolithography in the microelectronics industry. Read more about it in the article.

So, to round it up – it’s not always possible to get the wavelength you need for a specific application, due to limitations in the laser and in the materials and processes involved. But, nonlinear optical elements can allow the laser industry to reach further into more wavelength regions, enabling processes that are otherwise impossible to attain.