Spectralight is dedicated to the further development of low level laser therapy through the use of pulsed lasers. This blog is our way of sharing with you updates on our technology, our research and the latest news and experiences with pulsed LLLT.

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Obviously Spectralight’s core technology is laser pulsing and in this blog we are going to explore just what we mean by “laser pulsing” and how it works. Essentially pulsing means turning the laser on and off and there are a number of ways to do this, ranging from mechanical devices to electronic switching of the laser. Electronic switching is the most common method and is also how Spectralight’s PulseDrive operates. PulseDrive employs a high powered MOSFET to act as a switch that turns the lasers on and off very quickly.

Clearly when pulsing our lasers there are periods of time when the laser is “on” and periods of time when the laser is “off” and this will impact the average output power of the laser and therefore the dose of laser light, that the laser delivers. Dose is probably the most critical factor when it comes to low level laser therapy. Thus we must ensure that the correct amount of laser light is delivered despite the laser “off” periods.

With constant wave lasers, power output is a function of input voltage and current (P = I x V) however with pulsed lasers, we now need to consider RMS power (root mean square). RMS power takes into consideration the “off” time of the laser, which is a function of the type of waveform that is used to pulse the lasers. Rather than getting all technical here, let’s take a look at a couple of graphs.

For both of our graphs the vertical axis represents voltage and the horizontal axis represents time. Figure 1 depicts a constant wave laser with a 3 volt input drive. Figure 2 depicts the same laser with a pulsed input drive at 8 volts and a 40% duty cycle. Duty cycle is the ratio of laser “on” time to the laser “off” time. The result is that both lasers deliver the same RMS output power and therefore the same dose of laser light. However the difference is that the output power is delivered in very different ways. The second laser is delivering a much higher peak power but this is offset by periods of zero output. The end result being that the second laser delivers the very same total power as the laser driven with a constant 3 volts, however it also delivers higher peak power which may help to improve penetration depth of the laser light. And there you have it in a nut shell – that's how pulsed lasers work.

PulseDrive has been optimised for Aixiz 3.2 volt laser modules. An 8 volt peak-to-peak input drive is well within the operational parameters of these lasers.