Column: Lasers and Optics Interface

, is the General Manager of the Applied Systems business at Ocean Insight, an affiliate associate professor at the University of Washington, and has started and advised numerous companies in spectroscopy and in applications of machine learning. He has approximately 40 peer-reviewed publications and 6 patents. His work in practical optical spectroscopy, such as LIBS, Raman, and TDL spectroscopy, dovetails with the coverage in this column, which reviews methods (new and old) in laser-based spectroscopy and optical sensing.

Articles

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.

Advances in the Applications of Lasers for Bioimaging: Light Sheet Microscopy

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.

Expert Perspectives on Laser-Induced Breakdown Spectroscopy (LIBS)

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.

Broadband High-Brightness Sources 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.

Tunable Diode Lasers for Trace Gas Detection: Methods, Developments, and Future Outlook

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


Ultrafast Lasers in Spectroscopy—Moving into the Mainstream

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

Improving SERS Diagnostics with Hollow-Core Negative Curvature Fibers

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.


Combining Broadband Spectra and Machine Learning to Derive Material Properties

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.

Laser Ablation–Based Chemical Analysis Techniques: A Short Review

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.

Next-Generation Mid-Infrared Chemical and Biological Sensors: Combining Quantum Cascade Lasers with Thin-Film and Hollow Waveguides

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.