Intralase is based on Nd:glass

In the article “Ultrafast fiber lasers forge new microprocessing frontiers,” the author incorrectly refers to the Intralase laser as being based on Nd:YAG with 10 kHz repetition rate.

In the article “Ultrafast fiber lasers forge new microprocessing frontiers,” (July, p. 57; the author incorrectly refers to the Intralase laser as being based on Nd:YAG with 10 kHz repetition rate. Nd:YAG doesn’t have enough gain bandwidth to support femtosecond pulses. The laser platform in the Intralase system is based on Nd:glass. As far as the repetition rate is concerned, indeed Intralase started with 10 kHz in year 2000. The laser went through several redesigns and the latest model introduced in 2008 operates at 150 kHz, similar to the Zeiss/IMRA system.

Ruben Zadoyan
Director, Technology & Applications Center
Newport Corp.
Irvine, CA 92606

Technique enables high-speed 3-D microscopy

I enjoyed reading “Photonic Frontiers: Microscopy Techniques: The quest to see inside living cells is driving new optical microscopy” (May 2008, p. 73; Under fluorescence microscopy, you talked about the advantages of two-photon fluorescence, and mentioned Jeff Squier’s approach to rapidly switch between two focal planes.

I want to draw your attention to another approach that you seem to have overlooked.

We have developed and published a technique that allows microscopy users not only to switch between two focal planes but to randomly position the two-photon excitation volume at very high speed in 3-D. Patented acousto-optic scanning technology (U.S. Patents 7,332,705 and 7,227,127) supports inertia-free 3-D scanning at 50,000 sites/second. The fundamental technology was published in Journal of Biomedical Optics (J. Biomed.Opt. 10(6) 64038, 2005) and the application to imaging of neural activity was published in Nature Neuroscience (Nat. Neurosci. 11(6) 713, 2008). The technology was highlighted recently in Nature Methods (Nature Meth. 5(6) 464, 2008) and in Biophotonics International (July 2008).
Peter Saggau
Professor, Dept. Neuroscience
Baylor College of Medicine
Houston, TX

TruMicro Series 5000 was omitted

With interest I read “Ultrafast fiber lasers forge new microprocessing frontiers,” (July, p. 57; Unfortunately the TruMicro Series 5000 from TRUMPF is not mentioned. First shipped in October 2007, the TruMicro Series 5000 was the first high-power picosecond laser that did use a modelocked fiber seed oscillator combined with a bulk amplifier (based on a thin-disk regenerative amplifier) and reaches unmatched 50 W average power at 200 kHz repetition rate and less than 10 ps pulse duration.

With the TruMicro Series 5000, TRUMPF managed to combine the two most mighty technologies in the laser world—fiber and disk—in one product.
Dr. Sascha Weiler
Product Management
Schramberg, Germany

Editor’s note: In the same article we also inadvertently omitted Clark-MXR. For more information see the Clark-MXR Micromachining Handbook at

Hecht’s articles form an excellent reference resource

Jeff Hecht’s articles are the principle reason that I have been so vigilant in maintaining my subscription to Laser Focus World. I archive virtually all of his contributions dating back to the early “Back to Basics” articles, ultimately binding them into books at Kinko’s for easy reference. I do refer to them frequently. These articles are the equivalent of an on-going professional development course offered by the professor everybody waits in line to get—as interesting and relevant as a Feynman lecture, but far more applicable to those of us in the industry.
Mark Aceto
Vienna, VA

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