Columns | Column: Lasers and Optics Interface

Spectroscopy plays a critical role in both macroscopic and microscopic plastics detection, which is the first step in remediation, and also in the commercial replacement of plastics with biodegradable materials. This piece provides tangible examples of efforts being made today, including details on spectral hardware implementation, but more importantly provides proposals to the reader on how they can make a meaningful difference in their own world.

A recent investigation of the optical emission of plasma on industrial steel samples using LA-SD-OES and LIBS revealed new findings about the oxide composition of the slag layer.

A brief history of fiber-optic bundles helps us understand how this technology how it has evolved from use in telecommunications to enabling extraction of three-dimensional (3D) information from two-dimensional (2D) images.

A 3D printer can shorten the time to make prototype hardware for spectrometers from weeks to days—or less.

Accurately measuring and quantifying the perception of color is an ongoing challenge for scientists, but understanding spectroscopic techniques can help standardize color measurements.

Controlling methane is one of the highest-impact ways to reduce climate impacts, so its accurate measurement is essential. Spectroscopy offers valuable tools for this task.

The Covid-19 pandemic has led to extraordinary developments of both testing methods and vaccines. Can spectroscopy play a role in next-generation testing for Covid and other pathogens?

Laser-induced breakdown spectroscopy (LIBS) is an ideal method for elemental analysis of geological samples, and has been used by NASA on the Mars rovers. This article details the methodology and the most successful calibration and quantification methods to date.

A frequency comb is a laser source, with evenly spaced narrow lines, potentially useful for spectroscopy applications, particularly as a source or for alignment of the wavelength axis.

Tunable narrowband light sources are essential for measuring fluorescence, reaction energetics, and other challenging measurements in chemical, biological, and physical systems. In particular, the optical parametric oscillator (OPO) is an indispensable tool.

Advances in lasers are expanding the capabilities of LIBS and laser ablation techniques.

The unique strengths of LIBS-sample preparation optional, stand-off detection, portability, speed, and sensitive light element detection-point to future directions and potential for LIBS as a tool for soil measurements in precision agriculture.

An important class of nanoparticles made of “upconversion” materials has found a central role in sensing. These nanoparticles are used to convert longer-wavelength photons into shorter-wavelength fluorescence to detect temperature, pH, gas molecules, ions, and trace biomolecules.

Lasers allow advances for investigation of biological samples. Discussed here are some of the most interesting recent developments in light sheet microscopy for bioimaging, including a technique that allows for unique viewing of large, intact samples including biopsies.

LIBS has transitioned from a method found only in research laboratories, to a technique in wide use in commercial settings. Several leading LIBS experts share their views on how the technique has developed and where it is heading.

In the near past, discharge lamps, dye lasers, and optical parametric oscillators were the only useful sources for spectroscopy. New broadband sources, such as supercontinuum lasers, laser-driven plasma sources, and high-brightness light-emitting diodes (LEDs), are now available. We look at what these options offer for spectroscopy.

Tunable diode laser absorption spectroscopy is hitting the mainstream. Here, we look at the history of the technique, the current state of the technology, and future challenges.

A look at how high-powered ultrafast lasers are moving toward widespread use in spectroscopy and in industrial settings and the developments that are driving these changes

Novel optical probes using hollow-core negative curvature fibers can significantly improve the capabilities of Raman sensing, including surface-enhanced Raman spectroscopy (SERS).

With methods such as infrared, Raman, and LIBS, the spectral background contains a wealth of information about material properties of the sample. Now, such information can be derived by artificial intelligence and machine learning algorithms.

This review describes the most common approaches to laser ablation-LIBS and LA-ICP-MS-and provides an introduction to laser-ablation molecular isotopic spectrometry.

Mid-infrared (MIR, 3-20 µm) sensor platforms are increasingly adopted in chem/bio analytics, and applied in areas ranging from process monitoring to medical diagnostics. Due to the inherent access to molecule-specific fingerprints via well-pronounced fundamental vibrational, rotational, and roto-vibrational transitions, quantitative information at ppm to ppb concentration levels and beyond is achievable in solids, liquids, and gases. In particular, the combination of quantum cascade lasers (QCLs) with correspondingly tailored waveguide technologies serving as optical transducers – thin-film waveguides for liquid/solid phase analysis, and substrate-integrated hollow waveguides for gaseous samples – facilitates miniaturizable and integrated optical chem/bio sensors and diagnostics applicable in, e.g., exhaled breath analysis, food safety, and environmental monitoring.

Infrared reflectance and absorption spectroscopy have been practiced for decades. New capabilities in detectors and light sources are quickly changing the landscape in the near- and mid-infrared, where fundamental vibrations and overtone bands allow sensitive measurements in applications related to food safety, precision agriculture, energy, and smart manufacturing, to name a few.  This article outlines some of the most recent innovations and how they might be applied in real-world systems.

Vassilia Zorba of Lawrence Berkeley National Laboratory in Berkeley, California, discusses what her studies have revealed about the mechanisms of plasma emission at small scales and what she has found when applying femtosecond LIBS to the study of advanced battery materials.

Vincent Motto-Ros of Lyon 1 University, in Lyon, France, is combining the ability of atomic spectroscopy techniques to detect and quantify metals with the mapping approaches most often used with molecular techniques. He has combined laser-induced breakdown spectroscopy (LIBS) with electron microscopy to map the metals and metallic nanoparticles in biological tissue, as a way of studying the update and clearance of these materials by biological systems. In this interview, he discusses his work applying LIBS to biological analysis, including the methods, advantages, and future directions.

Pages 22–35 Rapid detection of coal and fly ash is significant to improve the efficiency of thermal power plants and reduce environmental pollution. Given its fast response, high sensitivity, real-time, and noncontact features, laser-induced breakdown spectroscopy (LIBS) has a great potential for on-line measurement in these applications. The direct measurement of particles and gases using LIBS was studied, and the method was shown to be effective for this application. 

The monitoring of the processes in steel and metal industry calls for techniques that are capable of measuring the composition of metallic alloys at a distance and on moving conveyor belts. In many cases, such as in the recycling of automotive scrap, the geometry of the objects to be analyzed can vary, and surface coatings can be present. In this paper, we discuss the application of LIBS to two industrial projects to illustrate how the above-mentioned problems can be faced and successfully resolved.

Nanostructured materials are expected to lead to the emergence of new products with enhanced functionalities. Their manufacture often requires the use of particles referred to as nano-objects, their aggregates, and their agglomerates. Laser-induced breakdown spectroscopy (LIBS) was deemed as a potential candidate for the detection of these materials in various contexts. This article discusses examples of the application of LIBS for workplace surveillance and process control of nano-objects.

This article explores the use of laser-induced breakdown spectroscopy (LIBS) for measurements of elemental concentrations and bulk properties of heterogeneous, earthen-based samples. Rapid field and industrial measurements of these matrices are difficult using traditional methods.

Users must be careful when developing material classification and calibration methods for LIBS. By following some guidelines, one can achieve relative standard deviation values of 2–3% for many types of analysis, and below 1% for homogenous samples.

In the study of global warming, obtaining good data demands widely deployed, accurate, and reliable sensors for identifying and understanding the origins, sources, and fates of greenhouse gases. Sensing technologies based on tunable diode laser absorption spectroscopy are starting to provide some of this critical data.

The choices for LIBS hardware are discussed in detail, particularly lasers and spectrometers, and the trade-offs between cost, size, and performance are illustrated.

An overview for those considering implementation of LIBS to solve a particular analytical problem, and an introduction for those interested in learning more about LIBS. Part I concentrates on the basics of the measurement and typical implementation.

Here, Martin Zanni explains two dimensional (2D) infrared spectroscopy, the role of lasers, and current applications, such as studying the kinetics of protein aggregation in diabetes.

Mid-infrared quantum cascade lasers, recently developed and commercialized, have unique properties that advance the analytical capabilities of IR spectroscopy in many ways. Bernhard Lendl of Vienna University of Technology in Austria explains these developments.

Although the choice of laser is still highly dependent on the application requirements, there are distinct fundamental effects attributed to the laser pulse duration that drive the ablation sampling process. Here, we explain the differences between nanosecond and femtosecond laser ablation.

A report on first results of the successful application of optically pumped semiconductor lasers in Raman spectroscopy of condensed-phase samples

The theoretical and experimental differences between high-brightness and low-brightness lasers used in a dispersive confocal Raman microscope system are compared.

The basic techniques of fluorescence correlation spectroscopy (FCS) are discussed as well as several applications, such as nanoparticle dispersion studies.

A few key steps will protect your samples and help ensure accurate results.

A Q&A with Jose Almirall, PhD, professor in the Department of Chemistry and Biochemistry and the director of the International Forensic Research Institute at Florida International University.

This month's column discusses the various multiphoton spectroscopy techniques and the lasers required for each approach.

This month's installment of "Laser and Optics Interface" describes CCDs and the new CMOS image sensors and cameras for scientific imaging.

Guest columnists Phil Taday and colleagues look at the emerging technique of terahertz spectroscopy and its move from the lab to the process world.

Performance gaps in the industry's earliest miniature spectrometers today have been mitigated by the ongoing improvement of gratings, coatings, mirrors, and other spectrometer bench optical components.

The author discusses the use of filters in optical microscopy and the advantages that have been gained as a result of developments in filter technology.

In this column, Guest Columnist Philip Taday explores the use of terahertz spectroscopy for tablet coating analysis.

The author discusses what the future holds for the field of optics.