Technology Forum: Optics/Lasers

From infrared to terahertz technology to lens and filter technology, lasers and optics are the foundations of spectroscopy research, and here, our panel of experts discusses all that is new and innovative in this area.

Joining us for this discussion are Rob Morris, Ocean Optics, Inc.; Alexander Bol'shakov, Applied Spectra; and Elizabeth Illy, Cobolt AB.

What is the single-most important advancement in lasers and/or optics that you have seen in recent months/years?

Morris: Advances in lasers over the last several decades have been nothing short of remarkable. Lasers have long since moved beyond military and medical applications to consumer uses – think of laser pointers, for example, or laser level tools used by do-it-yourselfers for remodeling projects.

But I am most interested in some of the advances being made in optics, particularly dichroics, which use patterning to manipulate light for all sorts of applications. Particularly intriguing is the integration of patterned dichroic filter arrays with standard CCD and CMOS detector arrays to provide multispectral imagers that are easier to manufacture and more accessible to the average researcher. Applications ranging from counterfeit detection to medical diagnostics will benefit from this new approach.

Bol'shakov: Most notably, the reliability of solid-state and spectroscopic diode lasers has improved in recent years. In the past, insufficient reliability prevented a more successful expansion of laser-based spectrometers into the marketplace. Also, the cost and size of lasers have decreased. New benchtop ultrafast and fiber lasers are now available for integration into spectrometric instruments, thus creating new analytical capabilities.

Illy Personally, I consider the announcement of a silicon laser to be a pretty impressive advancement in the area of lasers. It’s always seemed an impossible medium to observe lasing in and means potentially big advances in the areas of telecoms and computing.

How will advances in lasers and optics affect the pharmaceutical industry in the future? Homeland security?

Morris: Although this falls into the category of an incremental advance versus something more disruptive, there have been changes in optical technologies that enhance spectroscopy techniques used in pharmaceuticals processes. Better focusing of light, for example, allows lower-cost spectral systems to be used for dissolution measurements. That helps to control processes more efficiently and less expensively.

Bol'shakov: Laser-based spectrometers will continue to encroach into the fields of pharmaceutical analysis that are currently occupied by other analytical techniques. This is because laser-based instruments are generally faster and are often more compact. They offer analysis in situ, with high throughput, no chemical waste, and hence, reduce operational costs. Diode lasers are already broadly used in fluorescence cytometry and Raman spectrometry. These techniques are particularly important for pharmaceutical analysis.

Homeland security will benefit from the emerging stand-off chemical/biological detectors based on LIBS and Raman, and on combinations of the two. Lasing fluorescent polymer AFP is found as very sensitive to explosive vapors and particulates. Quantum cascade lasers and ultrafast lasers are making terahertz spectroscopy possible, which helps to see through people’s clothing – very useful for security, but scary to the public.

Illy: Lasers today are being used in more and more applications as we learn new, and revisit old, techniques which help uncover and understand the composition of materials. In particular, Raman spectroscopy seems to have a big future in helping us understand the right composition for the development of better drugs. And fluorescence-based high content analysis (HCA), which is based on lasers and is commonly used today in drug discovery to screen large volumes of potential compositions of drugs, is definitely helping the pharmaceutical industry to develop better drugs faster.

What advances in lasers and/or optics that we might think of as science fiction do you see becoming reality in the next ten years or more?

Morris: Developments in lasers certainly play a significant role in homeland security, both in weaponry and in communications networks. Today, these advances might not be as dramatic as the vision behind the Reagan-era “Star Wars” initiatives, but the more we witness technology catching up to science fiction, the less outlandish these big ideas seem to be.

On the optoelectronics side, there is technology today that comes very close to the “tricorders” familiar to fans of “Star Trek.” It’s not that difficult to imagine in the near future we’ll have handheld devices that provide detailed information about organic matter at the flip of a switch.

Bol'shakov: A chemical tricorder from “Star Trek” has just become a reality. A LIBS-based analyzer that reads mineral composition from a distance of 8 meters is being tested and will be sent to Mars in 2011. Similarly, stand-off Raman analyzers are emerging. As telecom progresses, ten years from now we may wish to see a digitally tunable array of pixels-nanolasers. In the pharmaceutical arena, for example, we may see a laser-based device beside a conveyer that will routinely count pills and perform random, instant chemical analysis, and specimen selection based on composition.

Illy:Teleportation or quantum cryptography is definitely something once reserved only for those with a science fiction fantasy. Whether we end up using it for more than encrypting information remains to be seen!

What is the biggest obstacle to these developments and advancements becoming reality?

Morris:You might get a number of answers to this question having to do with lack of technical knowledge (we don’t know what we don’t know), or decreased funding for research, or the retrenching effects of a sour economy, but to me it mostly comes down to good, old-fashioned capitalism. Yes, the government can help spur advances in technology – the recent spate of activity in solar energy is a good example – but ultimately, technology finds a home when someone discovers how to best exploit it to meet a specific need.

Bol'shakov:Eye-safety is probably the biggest obstacle to implementing laser-based standoff "tricorders." For other instruments that do not use an open-pass laser beam, there are remaining challenges involving insufficient robustness, laser lifetime, large size, and cost. Sampling irreproducibility in nanosecond laser ablation will continue to be a major problem.

How important will laser-based techniques such as LIBS be in the future?

Morris:They’ll be huge. While there are folks out there developing new lasers that satisfy the “What if?” nature of scientific endeavor, it’s the folks using lasers for a whole host of actual applications that will inspire new laser uses and improvements on existing challenges. The mantra of “faster, smaller, more powerful, and less expensive” has implications for a wide range of industries and applications, with many more ideas that haven’t even been imagined yet. To borrow a cliché, “if you build it, they will come” certainly fits well with the laser development of tomorrow.

Bol'shakov:LIBS has a 45-year history of development, but is still defining its niche in practice. The Raman technique is somewhat similar to LIBS, but simpler, and therefore, it has already seized a growing market share. The use of spectroscopic diode lasers is emerging in the area of isotope analysis, where they easily resolve key isobaric interferences that are ubiquitous and problematic for mass-spectrometers. Laser ablation or evaporation in such techniques as LA-ICP-MS and MALDI-MS has almost no alternatives that offer the same high local resolution and sensitivity together, and thus, their use will continue to grow. My company provides "green" solutions (no acid) in LA-ICP-MS and LIBS analysis, and makes spectrometers for academia, security, geology, ecology, and industry (in particular: semiconductor, photovoltaic, and automotive manufacturing). The LIBS market will grow as more commercial instruments become available and customers learn the advantages of LIBS.

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