It Seems D&S lasers have a competitor...

On: Tue, Jan 22, 02 10:45:13 PM

Jim McPherson wrote:

It seems Mr.Gentet has produced a "phase locking" laser diode system for holography. It's features look very very similar to the D&S system. The big difference is the price! Where the D&S system costs about $300, the "Samurai II" costs about $3000! I'd really like to see a comparison between these to laser drivers. Check out this link: -Jim


Jonathan - Wed, Jan 23, 02 02:39:52 AM

As good as the D&S driver is, it wasn't designed with "phase locking" as a feature. I've used the D&S driver for well over a year, and it is very good at what it was designed for - which was to provide stable, controlled power to the Mitsubishi diode. "Phase locking" is predicated on there being an absence of mode hopping, a primary source of frequency instability. Diode lasers are particularily prone to mode hopping unless their temperature is precisely controlled. Even then "phase locking" requires further steps must be incorporated into the design.

Colin Kaminski - Wed, Jan 23, 02 11:08:24 PM

I would not really say they are competitors. The D&S fringe lock seems to be accurate control of the output power. The phase lock on the Samurai seems to be achieved by bleeding a small amount of power from the laser beam and storing the frequency then comparing the present frequency with the past frequency and adjusting the temperature and power to match them. They are very secretive with their technology but I think that is what they do. Jonathan has been following their progress very carefully.

Jim McPherson - Thu, Jan 24, 02 08:32:50 PM

Let me ask this, and I know you don't know exactly... but. It seems that once the "phase" detector actually reads that something is wrong, then you can't fix the bad light that has already come out of the laser, you can only correct it. If so how does this help holography?

Colin - Thu, Jan 24, 02 10:13:17 PM

Because the fringes can shift 1/10 of a fringe before there is a decrease in diffraction efficiency you only have to make the detector more accurate than that. :-o

Guillermito - Sun, Feb 03, 02 03:20:18 AM

To be historically precise (and once again i'm doing a bit of advertizing for my french fellows, but who cares :), Yves Gentet sells the Samourai diode laser since 1995 or 1996, but at this time nobody knew him. Mr deFreitas contacted him with questions, and a little bit later sold his own simplified version of an holography diode laser. Guillermito (

Guillermito - Sun, Feb 03, 02 03:33:09 AM

Hmm... I guess i need more coffee. Let me precise a bit. I don't want to suggest Mr deFreitas copied the Samourai design. They seem to be very different anyway. I just wanted to say that the Samourai diode laser existed years before the DS one. Guillermito (

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