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How Responsible Purchase Decisions for Expensive Goods Like Lasers Are Done

Posted on 2024-04-23 as part of the Photonics Spotlight (available as e-mail newsletter!)

Permanent link: https://www.rp-photonics.com/spotlight_2024_04_23.html

Author: Dr. Rüdiger Paschotta, RP Photonics AG, RP Photonics AG

Abstract: Purchasing sophisticated and expensive equipment like a laser system requires detailed considerations concerning the requirements, technical specifications and various qualities of potential suppliers. Applying good practices can be vital.

Dr. Rüdiger Paschotta

Purchasing sophisticated equipment in photonics (for example, lasers, laser beam characterization instruments, or optical spectrum analyzers) is often something that needs to be done with great care. This is partly because a lot of money is involved – often on the order of 50,000 USD or more. In some cases, this is only for a first item of a type, with additional items to be purchased later. In addition, it is usually critical to get the right thing that works properly and is fully suited to the application. A bad purchase decision can cause a lot of damage, even beyond the cost of the equipment purchased: we must also consider all the time spent testing, identifying problems, trying to fix them, and so on.

It can therefore be essential for a buyer to apply good practices, and this article should help to improve them. Due diligence must be exercised – at a level appropriate to the amount of money spent and the importance of the goods purchased – and there is a responsibility to do so. While common sense naturally leads to good practices, as explained in this article, important aspects are easily overlooked if not carefully addressed.

Incidentally, similar considerations often apply to small items when purchased in large quantities. (Think, for example, of 10,000 tiny and inexpensive lenses that you want to include in your products). Again, you have cost issues that go far beyond the direct purchase price and risks that need to be minimized.

Identifying Suitable Suppliers

Obviously, a reliable list of suitable suppliers for the required items is an essential first step. Such a list does not have to be complete, but it should at least include the majority of the most relevant suppliers. You don't want to overlook an important supplier and realize only after the purchase that you had a much better option.

Oddly enough, some people think that the natural approach is to do a few Google searches. While Google is certainly a powerful search engine, it is not designed for this task and will not perform well: it will list some vendors multiple times, it may omit other important vendors completely, and it will return a lot of results that are not even related to places where you can buy such products.

What you need is a properly curated list of suppliers for a specific type of product. A photonics supplier directory, often called a buyer's guide, typically presents such lists of suppliers for many types of photonics products (over 750 in our case). Most of these buyer's guides will be more or less suitable for the purpose, but with differences in terms of accuracy of the listings (e.g. often listing some companies that do not offer the specific product you are looking for), ease of use, etc. Of course, I recommend our RP Photonics Buyer's Guide, which is unique in many respects, especially regarding its close integration with the famous RP Photonics Encyclopedia and its optimization of quality including convenience of use. It is the most natural thing to use what is very close to the frequently used encyclopedia article pages, where you often see some of the suppliers (our Advertising partners).

With such a resource, you will find it quite easy to produce a rather comprehensive list of potential suppliers. The greater challenge is thereafter to filter the results and finally select one of the found suppliers.

By the way, if you start with Google, it does matter what exactly you type in. For example, if you just search for ultrafast lasers, you will first find my encyclopedia article, then one on Wikipedia, then various supplier pages mixed with journal articles and other stuff that is not relevant to your purpose. To help Google better understand what you need (“search intent”), you can search for “suppliers of ultrafast lasers”. In this case, the first search result is a page called “Where to Buy Ultrafast Lasers” – a typical supplier page from the RP Photonics Buyer's Guide. In fact, people who start with Google will often soon continue their search with a more appropriate resource found in this way. Of course, it is better to start with a proven resource for a systematic approach, rather than randomly drifting around the web, hoping to get the best results that way.

Some may think that AI tools will take over such tasks in the future, but I am quite skeptical. The quality of a resource which is curated by a few experts in the field will be hard to achieve with an automated process. I expect that in the coming years many people will become more aware of the limitations of AI technologies, even though these clearly do fascinating things. So even for the first and simplest step – identifying potentially suitable suppliers – AI tools are unlikely to become sufficiently reliable, let alone usable for the steps that follow:

How to Select the Right Supplier and Product

For simple goods, you can often just pick the cheapest one. For sophisticated equipment like lasers, however, this approach is usually not applicable. The key is to ensure that the equipment fully meets your needs-that is, after all, the core purpose. When it comes to cost, the total cost of ownership will be relevant, not just the initial purchase price and, of course, the associated risks.

Unfortunately, it is not usually possible to make a reliable selection of a supplier based on the information available in a supplier directory, let alone a series of Google searches.

Understanding Your Needs

An important basis for everything that follows is that you have a good understanding of the exact purpose of the device and what is needed to accomplish it. This is why such a purchase decision cannot simply be made by an administrative person who does not have a detailed technical background. It needs to be done by someone with strong technical expertise who is also close enough to the concrete application – often a member of the team that will be using the equipment, and hopefully not the least experienced.

The technical aspects of selecting a device are too diverse to cover in a general article. I can only give a typical example using a pulsed material processing laser. First of all, it will need to meet a number of specifications on pulse properties such as pulse energy, pulse duration, wavelength and pulse repetition rate, further specifications on beam quality, possibly also power consumption, dimensions, etc.

Part of understanding your needs is knowing how important different aspects are to you. You may be able to compromise on some aspects but not others, depending on the application.

Many laser users do not have detailed technical expertise, and their primary interest may be in a non-photonics application. Of course, this does not mean that they can simply be excused from doing their due diligence before making an expensive purchase; after all, they don't want to get hurt. They may need to obtain competent and independent technical advice, e.g. in the form of technical consulting.

Another important measure is simply to discuss the requirements in sufficient detail within the team, including some of those who will later work with the purchased product. A little brainstorming can quickly reveal important additional aspects that need to be considered. This can be time well spent. So take the discipline to really do it with sufficient care.

The technical details mentioned above can be vital, but you will usually want to know more about a number of no less important aspects, as we will discuss in the following sections. Therefore, some tables of laser parameters will generally be of limited use; simply sorting such a table by pulse energy, for example, and picking the best supplier in that respect will not be enough!

Technological Questions

You often need to know what kind of laser technology the offered equipment is based on. This can have various implications on possibly unspecified details, device lifetime, possible variability of operating parameters, etc. Similarly, diagnostic devices may be based on different technologies with specific limitations. Therefore, you may need to consider the type of technology used, not just the details of a specific product. (For example, is a camera-based beam profiler right for you, or better one with a rotating knife?) Of course, you can only judge such things with a substantial technical background. Again, some brainstorming and possibly some technical advice may be required, or at least the study of some high-quality encyclopedia articles. Note that the time and cost of this is often nothing compared to the potential damage caused by a bad purchase decision.

It is also common for technical specifications to be incomplete, ambiguous, or otherwise questionable. This can happen in two places:

  • You need some specifications of your requirements.
  • Suppliers give you specifications of their products.

You may then need to ask specific questions to your colleagues or to a vendor. In the latter case, that also gives you a chance to test whether you can get help for responses in a reasonable time. In some cases, the quality of specification sheets are such that you may consider dropping a supplier from your list of candidates.

The best suited supplier will often not be the one who can reach the highest values of operation parameters like power or pulse energy, particularly if your requirements are not so extreme. Many other qualities can be substantially more important. In the following, we discuss more of those.

Considering Cost

Minimizing costs is, of course, a central aspect of purchasing. However, it is not only the direct cost of a purchase that needs to be considered. Even the cost of ownership (including consumables, maintenance, and the like) does not give you the full picture. Several other important things should also be considered, such as the efficiency of working with the equipment, the lifetime and reliability, the impact of service interruptions, etc. (Note that a device is acquired for a purpose, and the overall financial assessment must include not only cost but also how well the actual purpose is fulfilled.) Unfortunately, many of these things are more difficult to assess objectively than simply the purchase price.

In particular, strict budget constraints can end up costing more because they limit purchase prices while not limiting other financial consequences, such as wasted employee time and missed goals. Good management knows this, but not all management is good!

Additional Supplier Qualities

It is often not enough that a supplier can deliver a laser that fully meets the specifications. Some examples of other important questions:

  • Has the potential supplier worked with this technology for a long time, and what is its track record and reputation?
  • Can they provide potentially critical technical advice early and later? Will there be sufficiently helpful support if problems arise? How strong and generous are their warranties?
  • Will they be able to deliver the first laser quickly and possibly sufficient quantities later on (with the same or modified specifications)?
  • If you need a second supplier to reduce risks of dependencies: Are there “common modes of failure”, such as being dependent on the same original source?

For industrial applications in particular, such aspects will often need to be closely examined, but for research applications these things may be less critical, since only a single laser is needed, and it will be used by people with fairly detailed expertise. However, there may still be significant risks, such as jeopardizing the success of a research project within the time available.

It is often not easy to gather this information about a supplier. You can use the following sources, for example:

  • Check the supplier's website for information about their experience and track record. Several signals can be useful, such as years of experience, ISO or MIL certifications, clarity of product descriptions and data sheets, warranty terms, etc.
  • Ask the supplier representative a few questions and see how helpful the answers are.

Highlight red: Leverage past experience!

  • Ask your colleagues (on your team and possibly others): Have we bought from this supplier before? What was the experience? Did we get timely delivery? What was the quality of the product? If there were problems, were they diligent in trying to resolve them?

Document the Results

For every important decision, including purchasing decisions, you should create a document that records the work you have done. For example, write down the following:

  • What input did you get on the requirements? What final assessment did you synthesize from them?
  • How did you create your list of suppliers to consider, and what criteria did you use?
  • What criteria did you use to select a particular supplier and product?

Such a report can be valuable in many ways – for example:

  • The next time you make a purchase, you can use the document to quickly see what you need to check. (A checklist can be useful for this as well.)
  • If something goes wrong with the purchase, but your document shows that you properly considered certain relevant issues or alternative suppliers, you can deflect blame. (If you can't even reconstruct what you checked, you'll look unprofessional).
  • If mistakes were made, a post-mortem analysis will at least help avoid them in the future.

Note: Professionals occasionally make mistakes, but they take care to minimize the risks with effective and efficient procedures, and they learn from mistakes properly. Documenting the results of work is one of the essential practices to ensure good work.


Making responsible purchasing decisions for expensive and critical equipment is not easy. Many aspects need to be considered, starting with the detailed requirements, followed by the technical details of the products, and finally the various additional qualities of the suppliers. External help in the form of competent and unbiased technical advice may be needed to limit the risks involved.

In addition to the competence of the buyer, external constraints can also affect the quality of purchasing decisions. Examples include insufficient time to apply best practices and unrealistic cost constraints.

The search for suitable suppliers is only one of several important steps and should begin with the use of a well-curated supplier directory such as the RP Photonics Buyer's Guide. Note, however, that even the best directory cannot provide all the information needed to make a purchase decision; further research is required.

Some may find it inconvenient (or perhaps even excessive) to do so much work just to buy something. However, if you compare the value of a day or two of such work with the potential consequences of a project's success or failure, it should be clear what due diligence means in such cases.

You are welcome to provide comments below, and to tell your colleagues about this article, with which a lot of trouble can be avoided.

This article is a posting of the Photonics Spotlight, authored by Dr. Rüdiger Paschotta. You may link to this page and cite it, because its location is permanent. See also the RP Photonics Encyclopedia.

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