High-Transmission Precision Optics

Dr. Brian Manning, Application Scientist with Chroma Technology Corporation talks to AZoOptics about high-transmission precision optics.

Can you give us a brief overview of Chroma Technology and the field you operate within?

Chroma Technology Corp. was founded in 1991 by a group of individuals whose intention was to create a corporate culture that was different than what they had experienced before.

As well as creating a business model that was not only socially responsible to the community-at-large, they sought to apply that responsibility to the larger community of customers that approached them for assistance, regardless of the customers’ background or requirements. This business model took the shape of full employee-ownership, ensuring that each employee was responsible for not only their actions but ultimately accountable to the customer, as well.

From a very early stage, it became apparent that providing the customers with assistance that may go above-and-beyond the manufacture of an optic was key to our success. During the process of improving what came before (steeper bandpass cut-ons and -offs, deeper blocking/attenuation out-of-band, etc.), it became readily apparent that listening intently to the customer’s request was integral in the improvement of the optics.

In our experience, great wisdom can be gleaned by all parties by understanding the customer’s application in great detail in the spirit of true scientific collaboration. In this way, we have separated ourselves from other vendors by devoting our efforts into not only providing what has been requested, but also gaining a true scientific appreciation and understanding of how our products will be used.

We are often the first place people contact with ANY application question regardless of the possibility of making a sale (“Call Chroma, they’ll know”), a very large point of pride for us.

What are your key products?

We specialize in high-quality, high-transmission precision optics that provide high signal-to-noise in a number of fluorescence and other light-based applications and instrumentation. Our optics are used in everything from simple gel reader/documenting instruments to the latest iteration of STED/STORM/PALM/structured-illumination microscopes, from bread-board-based custom laser instruments to the simple teaching microscope used by the customer intending to determine the authenticity of vintage Gibson guitars. Any machine or instrument that uses light in its functioning could potentially use a Chroma optic.

We have recently begun to advertise high-transmission, ultra-flat dichroics and filter sets intended for use in TIRF (total internal reflectance fluorescence) microscopy. These were originally designed in conjunction with a customer-based requirement for astigmatism and interference-free optics necessary for this application. We have also begun a filter line consisting of magnetron-sputtered metal UV optics with deep out-of-band blocking and very high in-band transmission efficiencies.

How does your interference filter technology work?

Interference thin-film-coating operates on a reflection principle which modulates the wavelengths of light that are allowed to pass through the filter. In effect, thin-film interference filters work not by transmitting what they are required to transmit, but by blocking the transmission of all unnecessary light other than the proscribed narrow range that needs to be transmitted.

One of the most common questions we must ask our customers (and one of the least understood principles, generally) is for clarification of the filter’s out-of-band blocking properties.

The properties of the filter’s transmission band (center wavelength and band width) are only a small part of the puzzle that we have to solve with each customer (end-user or OEM). The larger part of the function of any filter is what wavelengths that filter CANNOT transmit, and that is often different from application to application.

One of your key specialities is the manufacture of interference filters. What unique capabilities do you have in this field that make you stand out from other manufacturers?

Chroma possesses a real desire to work with the customer to provide them with an optic that truly meets their needs and requirements. During our time in the market, we have prided ourselves as being true collaborators with our customers, listening to their needs, certainly, but also providing them with our impressions and suggestions when there is a disconnect between requirements and our production abilities.

We very infrequently have to tell a customer that we absolutely cannot meet their requirements, and even in those few cases, will attempt to work with the customer to find a viable solution that might not be ideal but certainly serviceable.

Having been “in their shoes” myself, I enjoy customer interactions that may extend beyond an immediate filter purchase but that allows me to discuss matters relating to the application that might suggest new research avenues for both the customer and Chroma Technology. To my knowledge, this level of support is unique in our industry.

Who are your customers in the market?

Chroma customers come from all walks of life, both within the obvious scientific and biomedical communities, but also from such diverse backgrounds as art history, aerospace and astronomy and machine vision technologies. Most commercial fluorescence microscopes come equipped with Chroma-built filter sets, but Chroma optics are also found in flow cytometers, medical endoscopes, plate readers and spectrophotometers.

Ultimately, our customers are the end-users of the instruments, but we also work closely with the instrument manufacturers to ensure that our optics fit their needs and requirements and therefore those of the end-user. Having had direct experience as one of those end-users, I truly appreciate those contacts that allow me to use my own research experiences in finding a solution to a real-world problem. Oftentimes, we must think on our toes to find that solution and part of the joy of my job is expanding my own understanding in order to appreciate the complexity of the problem facing the end-user.

What are the key applications for your interference filters amongst your customers?

Certainly microscopy applications have been our life-blood for many years. Of late, however, as scientific endeavours become more and more interdisciplinary and results dependant on multiple modalities and techniques, we’ve had more and more enquiries for optics to be used outside of microscopes.

Many genetic sequencers are fluorescence-based, for instance, and applications that only a few years ago were rather stagnant, to our eyes, are coming to the forefront again with improvements in those technologies. RAMAN spectroscopy and CARS microscopy are an example of this. Flow cytometry appears to be a methodology that ebbs and flows in overall popularity and research use, as well.

Also, with improvements in both power and cost of laser illumination sources, we have more and more customers who approach us for optics for bread-board-based systems or proof-of-concept-level OEM support that might have unusual geometries or beampaths. Being flexible enough to accommodate these customers as well as basic microscopists is yet another point of pride.

In what ways have Chroma worked with the life sciences industry for the application of Fluorescence Filters?

We have worked intimately with many of our customers throughout our history. In fact, part of what made our name was this interaction. Many of our catalogued filter sets are named after particular researchers who approached us for improvements in the sets and optics they were accustomed to using.

It was through this interaction that we were able to determine what combination of optics made the greatest difference in their signal quality. We also present during the development of the first 2photon confocal systems, producing barrier/emission and beamsplitter optics that were optimal for use with their near-IR lasers. Direct, first-hand experience has translated in our ability to streamline the process for the next customer.

For our industrial contacts, this same principle applies, of course. Since most OEM requirements are dictated, at least in part, but end-user needs, we feel very confident in our abilities to look at specifications and make suggestions and improvements to these whenever possible.

We’re also in a rather unique situation in that our direct interactions with end-users of all sorts allow us to sense when a new methodology or technique is entering the public consciousness. We were present during the early days of fluorescent protein work, the aforementioned CARS, TIRF microscopy and optogenetics to name just a few, working directly with the researchers and equipment manufacturers to cater to the needs of these new technologies.

How do you see the development of fluorescence analysis progressing over the next decade?

As methodologies and techniques continue to improve, and as the resolution limit continues to shrink via applications such as STED, we believe that the need for optics that do not adversely affect illumination/excitation beam profiles while still providing excellent transmission efficiencies will continue to grow. Also, as laser sources continue to become more and more powerful and less and less expensive, we envision that the blocking/attenuation requirements of our optics will also be challenged.

It appears that there is an almost constant return to older methodologies, as well, to mine any useful techniques that might improve upon current technology. There is a great deal of useful information and data in these older methods just waiting for an enterprising researcher with a vision to uncover. We expect that we will continue to be present, working with these researchers both directly and indirectly as they make these discoveries.

What are the challenges facing the industry at this moment in time and in the near future?

As biomedical funding continues to be adversely affected by the current economic climate, we face the same pressures as the rest of the biophotonics industry. When individual research labs face funding crises, often the first thing cut from their spending is consumables, including optics.

Many have already become entrenched, relying on core facilities or equipment owned and operated by colleagues to perform their experiments. This is certainly understandable and we’re cognizant of this pressure, since it affect us again both directly and indirectly. There are signs of improvement, but we worry that decreased funding levels may lead to stagnation in all branches of science.

On a happier note, the decrease in spending cash has had an interesting side-effect, namely a re-examination of current methodologies with an emphasis on improving these technologies. Researchers and manufacturers may not have the capital to spend as freely as they once did, but this does allow them the time and impetus to examine their current equipment more carefully, looking for ways to improve it or use it for an application they may not have experience in. This can also lead to the development of new applications, of course, and new business opportunities.

How do your coatings for biomedical instruments help improve the product’s performance?

Greater throughput is always a benefit, particularly in applications that might be light-starved. Making the most of the photons at hand is always necessary, even in basic microscopy. This becomes of paramount importance in applications such as RAMAN spectroscopy and 2-photon microscopy where signal levels are extremely low and often very difficult to separate from the illumination/excitation source because of the proximity of the two, spectrally.

The use of magnetron-sputtering technology in the production of our filters has allowed us to ensure that almost every photon is available in both illumination/excitation and detection/emission pathways. Plus, these filters provide deep out-of-band blocking/attenuation which further improves signal-to-noise.

Also, maintaining the excitation/illumination beam profile is becoming more and more important in a variety of applications. Our dichroic mirrors have been highly sought after since our production techniques are capable of maintaining the optical qualities necessary to eliminate the possibility of astigmatism or interference pattern generation.

How are your filter products used in astronomy and telescopic applications?

At the moment, most of our astronomy customers are amateurs who use our optics for imaging of the various spectral components of celestial bodies.

Imaging with a bandpass filters that transmit astronomically narrow bands through the visible and near-infrared wavelengths allows for increased image resolution. Our filters are often higher quality than what has been historically available in this industry and again, our higher transmission abilities give astronomers a greater resolution than what came before.

You recently developed new manufacturing facilities with excellent environmental credentials. Is sustainability an important issue for Chroma?

Sustainability is a natural progression of our Mission Statement and our identity as an employee-owned corporation. Upon hiring, we each accept a share of the responsibility in the sustainability of Chroma both in an economic and social sense. We have the typical responsibilities shared by any business to their customer base, but we also share no small amount of responsibility to our communities.

Most of us volunteer in our home towns in some capacity, whether using our time to staff local warming shelters or simply coaching our children’s sports teams.

These responsibilities also extend to the use of natural resources and maintaining a production process that has a minimal environmental footprint. The geographic area we are situated in (southern Vermont) is a naturally-beautiful area, and part of our responsibility to the community is to ensure that our presence here does not impact this beauty.

Your subsidiary 89North won the prestigious Prism award from SPIE at the end of last year. Can you tell us a bit about this event, and what effect it has had on 89 North and Chroma in the past 12 months?

The Prism Awards ceremony was a wonderful event and SPIE put on an excellent evening. The room was a “who’s who” from the photonics industries, representing a tremendous amount of exciting new innovations.  It was an honor to be among them.

The year since winning the Prism Award has been an exciting time for all of us. One always hopes to create a special product, but winning an award such as this truly validates all of our hard work and efforts. The Prism Award has brought us increased exposure and publicity, always welcome for small companies. Both Chroma and 89North are well aware of the impact that positive word-of-mouth can have on business.

Where can we find more information about Chroma Technology?

Chroma can be found online, by calling us at 800-824-7662 or by emailing [email protected].

About Brian Manning

Brian Manning, Ph.D is an application scientist with Chroma Technology Corp. Brian is responsible for assisting customers in finding optimal optics for a given application, as well as mentoring and assisting other customer service and sales colleagues in customer requests. During his time with Chroma, Brian has served on Chroma’s Personnel Committee and internal hiring and training teams as part of his employee-ownership duties.

Prior to joining Chroma in 2006, Brian completed a post-doctoral fellowship in cochlear neurobiology at the Massachusetts Eye and Infirmary/Harvard University and received his doctorate in Anatomy and Neurobiology from the University of Vermont in 2002 studying enteric (gut) neural circuitry. Brian has also worked purifying custom peptides and producing poly- and monoclonal antibodies for use in immunohistochemistry at Quality Controlled Biochemicals in Hopkinton MA.