Wavelength Tech Forum: Optics and Lasers

This month’s Technology Forum looks at the topic of Optics and Lasers and the trends and issues surrounding it. Joining us for this discussion are Rob Morris, with Ocean Optics, Inc., Lisa Tsufura, with Melles Griot, and relative newcomer to the LIBS community Daniel W. Merdes, with Penn State University.

How have advances in the field of optics affected spectroscopy in the past 5 years?

(Morris) The optics have become more sophisticated to better optimize spectrometer benches and setups, yet are still affordable and scaleable. I think, too, that spectrometer manufacturers are better able to have customized optics made for them that optimize the signal in a setup, as opposed to having to accept tradeoffs from optics makers because they built to the least-common-denominator markets.

(Tsufura) Polishing techniques such as magnetorheological finishing that are now available allow for better surface accuracy and low scatter. Better optics lead to higher system efficiency and better signal to noise. Advances in optical coating design and the usage of ion beam sputtering deposition allow for the production of sharp cut off filter designs with the suppression needed for higher levels of discrimination and wavelength purity, particularly for Raman spectroscopy. Optical developments from the telecom market have also benefited the spectroscopy market. Low cost Bragg grating manufacturing techniques developed for telecom are allowing more affordable gratings to be produced for use in spectrometers. Fiber optics are being considered for use on instrument bulk heads for remote sample signal delivery and reception or easy serviceability.

What are some recent significant developments in optics and lasers?

(Morris) In optics, the ability to better control filtering properties (i.e., allowing light to pass at some wavelengths but not others) seems very useful for spectroscopy. In lasers, like other technologies, performance is increasing even as sizes get smaller and portability is more achievable.

(Tsufura) Development of compact solid-state technologies, which are attractive for compact instrument development, affords higher levels of reliability. These include diode-pumped solid-state lasers, diodes, doubled diodes and LEDs. Research and development in areas of microfluidics, MEMs, micro and integrated optics and electronics show promise for use in even smaller low cost devices for the future.

In what spectroscopic applications do you see potential growth in the use of optics and lasers?

(Morris) Improvements in optics can help across many disciplines, but with improvements in lasers, techniques such as fluorescence, Raman, and laser-induced breakdown spectroscopy (LIBS) all benefit.

(Tsufura) Three main areas. Process and development controls for pharmaceuticals and drug discovery, the newer area of biohazard detection, and process purity and control in the food industry. Dual-purpose devices that can save time and cost will also become attractive. An example is the Raman microscope, which combines spectroscopy with the addition of microscopy for structure detail of contaminants which is of particular interest in the semiconductor industry and a possible consideration for protein crystallization processes needed for drug discovery.

(Merdes) Laser-induced breakdown spectroscopy (LIBS) will certainly be a large growth area.

What do you see in the future for this market?

(Morris) There seems to be a lot of interest in Raman and LIBS in particular, with the government getting involved in areas such as chemical and biological warfare agent detection. We envision many commercial markets, especially medical and pharmaceutical, benefiting as well.

(Tsufura) Smaller, better, cheaper, faster devices will help grow the market. We also expect to see more specialized, lower cost devices disseminated as pre-screen devices that can be delivered more en masse. Positive tests resulting from these pre-screening devices will only then need to be sent on for more sophisticated time consuming and costly testing when absolutely necessary. This might be of interest for the food industry, where initial testing might have to occur at site in the field. These simpler lower-cost devices could be affordable enough to consider using as audit devices to prevent future suspects from entering into the food chain to begin with.

(Merdes) Process control in industrial settings, specifically processes such as mining and sorting of metal waste where selection is based on elemental composition. Also, current LIBS applications that are now mainly confined to the laboratory, such as detection of environmental contaminants and forensic investigations, will move into practice.

Do you see portability as a trend in this area? If so, what are some developments we might see?

(Morris) In general, in most applications we run across, portability is desirable and opens up many new possibilities. One of the problems with lasers is that they've lacked portability, but that is rapidly changing. So, too, with other technologies that have traditionally been limited to the lab.

(Tsufura) Yes. Many of the opportunities for growth are for portable units and in some cases, disposable units. Biohazard devices are envisioned to be field-deployed in many cases with parts of the device to be disposed of once used. In other cases, portable units can be used where the samples cannot be readily brought into the lab or factory floor without risk of contamination or modification of the sample. Field units are envisioned for food or water product safety. Portable units, preferably battery operated, would be ideal.

(Merdes) Portable LIBS systems have already been developed, and as smaller and more reliable lasers become available this trend will continue because the technology itself is so amenable to field application.

What do you think?

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