RE:RE:RE:Sorry about that last one !The wavelnegth window refers to the action spectra of cytochrome c oxidase and not the ability of light to penetrate tissues.
According tio Juanita Anders (yes another leading authrity), she has a different view point of superpulsed:
COMPARISON OF LIGHT PENETRATION OF 810 nm AND 904 nm WAVELENGTH LIGHT IN ANESTHETIZED RATS J. Anders, X Wu USUHS Bethesda, USA It has been reported that 20 % of the output power of 810 nm wavelength light penetrated through rat skin and remained stable over a 150 sec irradiation period while there was an increase in light penetration of 904 nm wavelength super-pulsed light over the 150 sec ( Photomed Laser Surg (2012; 12: 688–94.). The purpose of this study was to reexamine the penetration of these wavelengths of light. The lasers used were: 808 nm wavelength (B&W Tek) (output power 1 W, CW) and 904 nm wavelength superpulsed (Irradia) (20 W, mean output power 60 mW, 5 kHz).The power density was measured by a near infrared detector (B&W Tek, Inc). An incision was made through the skin and gastrocnemius muscle of anesthetized rats. The detector was placed under the muscle or skin. Experiments were done on laser emission stability. Once stability was reached, data were collected at 0, 10, 30 sec and every 30 sec for a total of 4 minutes. The 904 nm wavelength laser required 10 minutes to stabilize. If power density measurements were taken during this time, light penetration appeared to increase over time of irradiation. This increased penetration was eliminated once the output reached stability. The percentage of light transmission through the skin was: 808 nm laser=24.63 %, 904 nm laser=19.94 % and skin and muscle: 808 nm laser=7.24 %, 904 nm laser=4.01 %. Based on these data, penetration of 810 nm wavelength light through tissue is greater than super-pulsed 904 nm wavelength light.
My point being, it's not about depth of penetration anyway and there's no consensus.
As far as action spectra of CCO goes, the world's authority is Tiina Karu - she discovered the main mechanism of action of LLLT and trumps any expert you want to rebut with:
A recent paper from Karu's group [11] gave the following wavelength ranges for four peaks in the LLLT action spectrum: 1) 613.5-623.5 nm, 2) 667.5-683.7 nm, 3) 750.7-772.3 nm, 4) 812.5-846.0 nm.
[11] T.I. Karu and S.F. Kolyakov, Exact action spectra for cellular responses relevant to phototherapy, Photomed Laser Surg 23 (2005) 355-61.