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Thread: DPSS laser - whats inside the diode?

  1. #1
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    Default DPSS laser - whats inside the diode?

    I am wondering, if i was to take a DPSS diode, cut it in half with a hex saw, what would the inside look like?

  2. #2
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    A mess :lol:

    Jim

  3. #3
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    I'd suggest a more subtle method of opening the laser .

    A DPSS laser is actually more than a diode. The green lasers, for example, have an IR laser diode emmiting 808nm. After the diode you can find a collimating lens (sometimes it's not used), then the light goes to a crystal which lases at 1064nm (among other lines). That light is then passed through another crystal which doubles the frequency (halves the wavelength) to 532nm, then an IR filter and some other collimating lenses.

    So, in the end, if you don't destroy everything, you'd end up with the diode, a couple of crystals (usually bonded together), an IR filter and a couple of collimating lenses.

    Other DPSS units will differ in the crystals used, and perhaps in the arrengement, but will essentially be the same
    Remember the future?, That'd today, as you imagined it yesterday.

  4. #4
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    Default Re: DPSS laser - whats inside the diode?

    Quote Originally Posted by Evolve
    I am wondering, if i was to take a DPSS diode, cut it in half with a hex saw, what would the inside look like?
    I'm a bit puzzled by your question. Are you wondering what the inside of a DPSS unit looks like? If so, then JKaier3000's answer is what you're looking for.

    On the other hand, if you really meant "what does the inside of a laser diode look like"... Then that's something different; DPSS lasers have a diode laser (the pump diode) at their heart, but they are much more complex than just a simple diode laser. Assuming you were interested in what a laser diode looks like, I'll take a stab at an answer:

    A diode laser is essentially a small chunk of silicon. The top half has been "doped" (ie: had an impurity added to it when it was made) so that there are a few extra electrons in the crystal lattice that are free to move around. Likewise, the bottom half has also been "doped" so that there are "holes" in the lattice structure where a freely moving electron could easily "drop" into. The area in the middle where the two different materials touch (the boundary region) is where the lasing action takes place. (it is *really* small; on the order of a few milimeters long and in some cases less than a milimeter thick!)

    As voltage is applied to the diode, electrons gain energy and are pushed across the threshold between the two different types of silicon into the boundary region. When one of these free electrons "drops" into a hole in the boundary region, it looses energy and gives off a photon of light.

    The edges (faces) of the crystal are cleaved so as to be flat and parallel to each other, and this boundary between the crystal and the surrounding air acts as a mirror. Thus you have the makings of a fabry-perot resonator. As the light bounces back and fourth between the faces of the crystal, freely moving electrons are induced (or should I say stimulated, from the "stimulated emission" part of the word LASER) into droping into a nearby hole, thus giving up their energy and releasing another photon, which adds to the intensity of the growing light beam. (Sounds a lot like every other laser, eh?) 8)

    Eventually, the beam overcomes the boundary reflectance at the face of the crystal, and you get laser light out. Of course, depending on the specific properties of the crystal, plus the temperature of the unit, and the voltage and current applied, you may end up with IR output, red output (and anything from 670nm to 635 nm), or even blue output (from 442 nm for the Nichia diodes to 405 nm for the "blue-ray diodes).

    Adam

  5. #5

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    Buffo:

    I am proud. That is probably the most concise and accurate answer I have ever seen to date.

  6. #6
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    ops: Thanks Spec!

    Glad to help out. 8)

    Adam

  7. #7
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    Wow... I learned something today... Thank you! Can I go back to bed now? :roll:
    Love, peace, and grease,

    allthat... aka: aaron@pangolin

  8. #8

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    interesting topic!
    you can do it and tell us the result!
    MSN:wzcdehao@hotmail.com
    E-mail: wzc@viasho.com

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