I just read Jeff Hecht's article in Laser Focus World titled "Spectrometers and Spectroscopy: Looking Back/Looking Forward: Spectrometers and spectroscopy get faster, better, and cheaper," and I thought the article was very well written and covered many of the key points in the evolution of miniature spectrometers. I was also excited to see that he cited an article that I co-authored in LFW back in May 2013.
I think you left out one of the major milestones in the miniaturization of Raman spectrometers—the commercialization of the volume Bragg grating (VBG)-based external cavity diode laser by Innovative Photonic Solutions (IPS) in 2003. I know this statement may seem biased because I am currently employed by IPS, but I had been a customer of IPS for six years prior to joining the company in fall 2013, so I can speak with both perspectives. The reason why this laser was so important is it allowed systems integrators to have a compact, low-cost, and low-power-consumption excitation source that was wavelength- and power-stabilized over a wide ambient temperature range. This resulted in the IPS laser being used in most of the first-generation "handheld" Raman spectrometers. Since then, the VBG-stabilized diode laser has become the industry standard in Raman spectroscopy—in both handheld and laboratory systems.
A few years after the initial release of the VBG-based diode laser, IPS again revolutionized the world of handheld Raman when they came out with the first fully integrated, VBG-stabilized diode laser with a collimated output in a TO-56 package (see photo). This even further reduced the size and power consumption, allowing for the smartphone-size Raman spectrometers that now fit in the palm of your hand and run off AA batteries.
IPS has historically been really bad with PR and over the years, our sales have primarily been OEM and private label; therefore, outside of the Raman spectroscopy community, not too many people are aware of IPS's impact. I know it's too late to get any of this into the article, but I figured it couldn't hurt to fill the gap in the story.
Again, overall I really liked the article and I have already sent it to a few friends.