As happens around this time, we find ourselves on the threshold of a new year – and what a year it will be for the photonics industry! The International Year of Light kicks off in January with festive opening ceremonies in Paris, but the calendar started filling some time ago. You can see the list of exciting events to be held around the world at the official website, www.Light2015.org. Perhaps you and your organization have special commemorative activities planned that you would like to add? Photonics Media, ourselves no strangers to celebrating light and light-based technologies, is proud to be an IYL2015 media sponsor. We will cover IYL2015 in the pages of Photonics Spectra and all of our other publications, as well as on our website at Photonics.com/IYL2015Photonics.com/IYL2015, where we will collect all the articles and images that we publish and that come our way. Speaking of celebrating, this issue, full of shining examples of some of the latest technological advances in photonics – from OPO-based photoacoustic spectroscopy to automated fiber aligners – is just a mirror ball away from being a real shindig. In our cover story, Sauli Sinisalo of Gasera Ltd. and Håkan Karlsson of Cobolt AB reveal a promising technology aimed at trace-gas detection and analysis for environmental or atmospheric monitoring, industrial process control or medical diagnostics. Read the article, “OPO-Based Photoacoustic Spectroscopy Speeds Up Gas Analysis,” beginning on page 30. Also in this issue: • “Optical Delay Lines: Key to Time-Resolved Measurements,” by Dr. Ali Eftekhari of Newport Corporation, on page 35. • “Mounting Precision Enhances Laser Performance,” by John Wingerd of Siskiyou Corporation, on page 38. • “Active Alignment Techniques Improve Lens Centering,” by Trey Turner, Matt Lachapelle and Roger Kirschner of REO Inc., on page 42. • “Automated Fiber Aligners Improve Packaging,” by Stefan Vorndran and Scott Jordan of PI (Physik Instrumente) LP, on page 45. We write in every issue about the latest in light-based technologies, but we’ve all heard the adage that a picture is worth a thousand words. The continuing story of light is one that we feel should also be told through images and video. That’s why we produce the Light Matters Weekly Newscast, found at Photonics.com/VideoGallery. If you haven’t seen Light Matters lately, you’re in for a treat. We have also begun adding video definitions to our Photonics Dictionary. We are working with local schools and organizations to record demonstrations of photonics terms in lab settings with the latest equipment. Check it out, and if you would like to learn how you can contribute terms and video definitions to the Dictionary, send me an email. Enjoy the issue. As always, I invite you to contact me at karen.newman@photonics.com. And don’t forget to share your story of light with the world.