Highlights from “What’s Nu” May 2026

This month, Spectroscopy’s “What’s Nu” newsletter paid homage to the laser, which has evolved from a theoretical concept into arguably the most vital tool in the modern spectroscopist's arsenal today. In this Q&A overview, we explore the highlights from this newsletter, touching upon the key topics that researchers are talking about.

How did lasers become important scientific instruments in spectroscopy?

Originally just a concept, lasers first began its progression to scientific instrument thanks to Arthur Leonard Schawlow.¹ In 1958, Schawlow and his coauthor Charles Hard Townes, recipient of the 1964 Nobel Prize in Physics for his maser work, published a landmark paper in Physical Review that provided the theoretical analysis for extending stimulated emission from microwave frequencies into the optical spectrum.^1,2 Previously, researchers were forced to rely on arc lamps, discharge tubes, and thermal sources that emitted broad, unmanageable bands of light.¹

While these methods were somewhat helpful, the problem was that these traditional energy/light sources lacked intensity and directionality, which severely restricted the precision of measurements.¹ Schawlow and Townes realized that a coherent optical oscillator would provide monochromatic, highly collimated, and extraordinarily intense light, allowing for the selective excitation of individual atomic and molecular transitions with unprecedented resolution and sensitivity.¹

When did lasers go from a theoretical concept to actual instrument?

It was from this theoretical foundation that the laser came into existence. In 1960, Theodore Harold Maiman demonstrated the first working ruby laser at HRL Laboratories.^1,2 Maiman’s success confirmed the Schawlow–Townes concept, providing researchers with a light source whose spectral purity and brightness exceeded anything previously available to the scientific community.^1,2

In atomic spectroscopy, this facilitated Doppler-free measurements and the precise determination of hyperfine transitions. These advances led to more accurate atomic clocks and the determination of fundamental constants.^3,4 Molecular spectroscopy saw a similar revolution, particularly in Raman spectroscopy, where lasers replaced mercury arc lamps.^3,4 This shift increased signal intensity by orders of magnitude, making it possible to routinely analyze weak scatterers, biological samples, polymers, and pharmaceuticals.^3,4

The impact of this technology eventually expanded far beyond the laboratory into diverse fields like atmospheric monitoring, combustion diagnostics, and semiconductor characterization.⁵ Modern techniques such as cavity ring-down spectroscopy, femtosecond pump–probe experiments, and optical frequency comb spectroscopy all trace their lineage back to the Schawlow–Townes vision.⁵ Schawlow’s work earned him the Nobel Prize in Physics in 1981, recognizing how his insights reshaped analytical science.^1,5,6 Today, the laser is being used to measure trace gases at parts-per-trillion levels to probing ultrafast chemical reactions. ^1,5,6

Apart from lasers, what other topics did “What’s Nu” cover?

Our May newsletter also explored topics in chemometrics and regulatory adherence. For example, a “Chemometrics in Spectroscopy” column, the 250^th by the authors, was highlighted, which explored eliminating sampling repack variation in near-infrared (NIR) spectroscopy. Heterogeneous powdered samples often yield inconsistent optical readings when reloaded into a spectrometer, which is a physical phenomenon that compromises the accuracy of quantitative models.⁷ The column highlighted a new mathematically rigorous algorithm that utilizes the Lagrange Method of Undetermined Multipliers to separate systematic spectral changes caused by physical rearrangement from actual chemical data.⁷ This advancement addresses the limitations of traditional "fixes" like spectral derivatives, which often fail to isolate repack errors from other noise sources.⁷

What is the “hidden overfitting crisis” in chemometrics?

May’s “What’s Nu” newsletter also tackled the "hidden overfitting crisis" in chemometrics. A recent “Analytically Speaking” podcast episode tackled this issue head-on. Podcast host Jerome Workman, Jr. spoke with Professor Rasmus Bro, who discussed how accessible machine learning (ML) tools have led to widespread model misuse due to poor data quality and flawed validation.⁸ In the episode, Bro advocates for "validity by design," emphasizing that rigorous experimental planning and domain knowledge are the only ways to ensure models are robust, interpretable, and scientifically sound.⁸

What did “What’s Nu” cover about analyst training?

The last article highlighted in “What’s Nu” was a recent “Focus on Quality” column that explored why analyst training needs to move beyond a "box-ticking" read-and-understand approach.⁹ The article highlights that poor standard operating procedure (SOP) quality is a primary compliance determinant. Columnist R. D. McDowall recommended in his article that organizations enact a three-phase hands-on method that involves demonstration, supervised execution, and independent execution, to ensure true competence and regulatory adherence.⁹

References

1. Schawlow, A. L.; Townes, C. H. Infrared and Optical Masers. Phys. Rev. 1958, 112 (6), 1940–1949. https://doi.org/10.1103/PhysRev.112.1940
2. Maiman, T. H. Stimulated Optical Radiation in Ruby. Nature 1960, 187, 493–494. https://doi.org/10.1038/187493a0
3. Nobel Prize Outreach AB. Arthur Leonard Schawlow Facts
4. Feld, M. S.; Letokhov, V. S. Laser Spectroscopy. Sci. Am. 1973, 229 (6), 69–72. https://doi.org/10.1038/scientificamerican1273-69
5. Picqué, N.; Hänsch, T. W. Frequency Comb Spectroscopy. Nat. Photonics 2019, 13, 146–157. https://doi.org/10.1038/s41566-018-0347-5
6. Nobel Prize Outreach AB. 1981 Nobel Prize in Physics
7. Mark, H.; Workman, Jr., J. Development of an Algorithm That Minimizes/Eliminates Sampling Repack Variation. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/development-of-an-algorithm-that-minimizes-eliminates-sampling-repack-variation (accessed 2026-05-27).
8. Workman, Jr., J. Ep. 45: Overfitting in Chemometrics: Designing Models That Truly Work. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/ep-45-overfitting-in-chemometrics-designing-models-that-truly-work (accessed 2026-05-27).
9. McDowall, R. D. How Effective Is Your Analyst Training? Spectroscopy. Available at: https://www.spectroscopyonline.com/view/how-effective-is-your-analyst-training (accessed 2026-05-27).