Commercially available ultrashort-pulse laser technology: Part I – Lasers

While their contribution to the total industrial laser market is still quite small (less than 10%), ultrashort-pulse (USP) laser revenue shares are growing faster than possibly any other industrial laser market sector and growth forecasts for the next few years look appealing. USP lasers, which I define to be picosecond and femtosecond lasers, could soon be a large-enough segment to actually have their own category in market forecasts, which they do not really enjoy now. Even well-known industry analyst Allen Nogee typically does not track femtosecond or picosecond lasers, except for special reports. According to Nogee, “It is not a trivial task to count all of them because there are many smaller companies producing just a small number, compared to CW [continuous-wave] lasers, which have to be sold in higher volumes to make money. Many companies are very niche and small.” This is very true, but I have observed the excitement in the USP market both in technical talks, which could open up vast new applications, and at exhibitions, where vendors are all talking about growth.

What has changed since 2015, when I last presented the laser tables? First, most laser manufacturers now provide femtosecond and picosecond solutions. For some, it is one package that has tunable output, and for others, it consists of several models all operating in some specific regime. Instead of looking at femtosecond and picosecond lasers separately, I have grouped them all under USP lasers—which is consistent with how industry analysts look at it, for the most part. This eliminates considerations of whether a laser is picosecond or femtosecond, as they are all USP lasers. These lasers are more of a ‘commodity’ than they were a few years ago. However, USP lasers themselves are necessary, but not sufficient, as successful implementation of the technology also involves optics, system integration, and process development. Margins on USP lasers have probably fallen for the most part with increased competition, but volumes are much higher. The USP market segment has been predicted, by market analysts, to grow at a compound annual growth rate (CAGR) of 25% until 2024, with the largest markets in North America and Asia and with a vast number of users in the medical market envisioned.

As if the task of tracking USP laser manufacturers is not trivial, then tracking all of the other ‘components’ of the equation becomes overwhelming. There are many companies in many countries, notably China, who are, or say they are, involved in the USP laser market, but in order to make things manageable, I have adhered to the following:

• USP lasers and optics: Includes all products that are marketing internationally
• USP laser systems: Includes all companies that are selling or marketing USP systems in the U.S.
• USP contract manufacturing: Contract processors limited to the U.S. only

Even with the above restrictions, much of the data can be observed and extrapolated. It is my opinion that the USP laser is now not the bottleneck or weak point in a processing system and is but one (a very important one, mind you) of a number of different components that are all required in order to effectively use a USP laser to its fullest potential. In fact, USP lasers themselves have for the most part plateaued on the technology curve, with most manufacturers having future plans for higher power, lower cost, smaller size, etc.—which are all nice, but are sales- and engineering-driven, not marketing- and innovation-driven.

The really great news is that the applications are—again, in my opinion—far down on the technology curve and new applications will fuel growth across the board for laser manufacturers. We have seen a lot of consolidation among laser producers in the last few years, mostly by acquisition, but new companies have sprung up at a much-faster rate than companies have been acquired or that have just disappeared. While only a few companies have simply ‘gone away’ (Raydiance, for example), most have thrived and frankly, if a company cannot survive in this growth climate, it probably shouldn’t, as it probably has either a bad business model or a bad product.

Lasers

Let’s define an industrial USP laser. For the purpose of this article, the laser must have a pulse length <1 ns and preferably <20 ps. It must have single pulse energy of 10 mJ for femtosecond and more for picosecond. The laser must be capable of running up to 100 kHz repetition rate (typically 100 kHz to 1 MHz are used). The power should be ‘usable power,’ where it is remembered that output power (W) is the product of pulse energy (J) times repetition rate (s^-1):

E_pulse × Rep Rate = P

Power should be achieved without too high a repetition rate (unusable) or too low an energy per pulse (again, unusable). Finally, the laser must be ‘industrial,’ as outlined below:

• Be price-competitive, but customers will pay for proven quality
• Be ‘packaged’ well with a small frame, but easy to access and service
• Have all necessary electrical and triggering interfaces to optics, motion, etc.
• Be reliable for 24/7 operation
• Have company backing post-sale
• Have usable repetition rates and energy per pulse; harmonics, if available, must have sufficient pulse energy after frequency conversion
• Have reasonable delivery times

Data

I sent questionnaires to approximately 100 people at 50 different companies—some multiple. Most were personal contacts from the 2019 USP laser events such as SPIE Photonics West (San Francisco, CA), the UKP Workshop (Aachen, Germany), and LASER World of PHOTONICS (Munich, Germany). There were four categories, as stated above. For those companies where I did not have personal contact, I got information from their published websites and included the data—many attempts at contacting generic company e-mail addresses got no response at all. Twenty-two USP laser manufacturers were contacted and, of these, 16 replied to the initial inquiry, while subsequent responses presented in the updated table show that all but two of the 22 companies (91%) in the final tally did provide direct input. All companies were included whether responses were received or not based on information on their websites (this data is italicized in the table). There are other Chinese companies—Huaray and Raycus, for example—that are big in China and should probably be watched as well, as they are appearing at different venues. Also, a few companies were excluded because they have advertised power levels that are more useful for metrology or other applications rather than micromachining.

Comments

Currently, most applications for USP lasers are using the fundamental infrared (IR) wavelength because they follow the long-pulse (nanosecond) trend. Therefore, many companies are focusing on this wavelength, especially all fiber lasers where the pulse energy is not sufficient for harmonic generation. Fiber lasers do not typically have sufficient pulse energy to easily convert, especially beyond second-harmonic generation. However, double- and triple-frequency lasers definitely have applications where either the material interaction is better with shorter wavelengths or smaller achievable feature size is required. For those companies that answered the question about future plans, most cited that lower cost, higher power, and harmonics were more important than shorter pulse length. In fact, many applications for femtosecond lasers are actually most efficient at close to 1 ps and shorter is not always better.

There is not sufficient-enough space to go over each entry, but the table should allow easy comparison. Note that there is no entry for price, as this is dependent on location, laser model, power, harmonics, and other factors. It is expected that lasers be priced rationally in an environment of increasing competition, but people are also willing to pay for quality and performance if these can be demonstrated.

There are many different kinds of companies represented in the table and a few of these will be discussed. Of the companies listed, some are dedicated to USP and, in particular, femtosecond lasers. Light Conversion (Vilnius, Lithuania) has 25 years in the USP industry and Amplitude Systèmes (Pessac, France) has a tenure that is almost as long. Both started out as small entities devoted primarily to femtosecond laser development and are now mid-size companies with a global presence. Technology for both companies is developed in-house or with local academics. Several models are available in IR, second-harmonic generation (SHG), triple-harmonic generation (THG), and more. They have excellent support, fair prices, and are industry leaders in providing fiber oscillators and free-space optics to get higher harmonics. Both also support ongoing applications development and give frequent presentations at technical venues, as well as essentially 100% dedicated to USP processing.

Lumentum (San Jose, CA) is a member of the Industrial Laser Solutions Billion-Dollar Club (largest suppliers by industrial laser product revenues) and this company makes one of the most-robust picosecond lasers—but only a picosecond laser. Industrial lasers are only a fraction of their total sales and picosecond lasers only a smaller fraction of that. They do have a worldwide presence and their UV laser has very good reliability and lifetime. They also have a very good applications lab with all the right equipment, not just the laser, and have a strong focus on picosecond applications. 

There are a few companies that I call ‘one-stop shops.’ Two examples are Clark-MXR (Dexter, MI) and Spectra-Physics (Santa Clara, CA). These companies provide only the laser or they will build a laser subsystem or a complete laser processing system. Spectra-Physics has many models of USP lasers, from the low femtoseconds to picoseconds, and provides optical assemblies, motion components, etc. The company is worldwide and part of a larger entity (MKS Instruments; Andover, MA). USP is currently a small but important and growing part of the business and the company's focus is on precision, not power. Clark-MXR, a pioneer in USP technology, provides only femtosecond solutions. It is still a smaller company, but it has probably been involved in femtosecond laser processing longer than anyone. It manufactures femtosecond laser production systems and provides job shop/contract manufacturing as well.

YSL Photonics (Wuhan, China) is the only Chinese company to respond to my inquiries, which suggests to me that it is serious about market penetration outside of China--also, its responses were complete and clear. It provides the laser, which is tunable from 400 fs to 10 ps, with harmonics available. It is close to big markets in China, and is looking to do business in Europe and the U.S. It has announced a 1 kW femtosecond laser at the end of 2019, and future plans call for increased capacity for lower-power models.

Conclusion

What is the total world market for USP lasers? I asked this question and the top response was "no response." The next was "proprietary – cannot comment" and the third was "I don’t know." Answers ranged from 100 to 1000 lasers per year in the U.S. and 1000 to thousands worldwide. I think that a realistic range is 200–300 in the U.S. and 2000 in the world, with both growing. But remember that these numbers do not include surgical applications, metrological applications, or other non-materials processing applications. Also, it is hard to define, for instance, the number of lasers ‘sold’ in any one country because the laser is sometimes made or bought in one country and shipped in a system to another.

As mentioned earlier, the laser is a fundamental component of any laser processing system, but it needs more than just the laser. In "Commercially available ultrashort-pulse laser technology: Part II – Optics, Systems, and Contract Manufacturing," which will run in the March/April 2020 issue, I will review USP optics providers, system manufacturers, and U.S. contract manufacturers.

RONALD D. SCHAEFFER, Ph.D. ([email protected]), is an Editorial Advisor to Industrial Laser Solutions and the CEO of HH Photonics, New Ipswich, NH.