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You may have heard the term hybrid laser used to describe silicon lasers or laser arc welders in the semi-conductor industry. In the marking and traceability sphere, however, “hybrid” describes diode-pumped solid state lasers that have been modified with the goal of improving its performance, such as an S-MOPA laser (Solid-State Master Oscillator Power Amplifier).
Hybrid technology, of any kind, can be very appealing: combining two technologies to bring various benefits together into one product.
In manufacturing, the prospect of being able to buy one machine for multiple reasons, or for enhanced benefits, is especially enticing if the machine promises increased efficiency or, if the price is right, cost savings.
If you’re considering the purchase of a hybrid laser for part marking, you should understand its components and how they work together.
What is a Hybrid Laser?
Essentially, a hybrid laser is a fiber and YVO4 laser oscillation methods combined into one product.
Hybrid lasers, at their core, are diode-pumped solid state YVO4 vanadate lasers, with some modification.
The popular hybrid laser on the market today is an S-MOPA. You’ll see that described as combining a YVO4 laser marker with a fiber laser marker.
To break this down, there are a couple of core components to examine within the laser equipment:
- Oscillator: The master device that has an optical resonator in order to circulate and amplify the light into a laser beam.
- Gain medium: Located within the oscillator’s resonator to provide wavelength.
- Laser beam propagation: Can be in free space or in a fiber.
First, let’s explore those two oscillators:
Oscillator: YVO4 Laser
Laser Type: Solid-State, Multi-Emitter Laser Diode
Gain Medium: Neodymium-doped Yttrium orthovanadate crystals (Nd:YVO4)
Laser Beam Propagation: In free space
YVO4 technology uses laser diodes, which must pump a gain medium to produce the laser beam wavelength. The laser beam is propagated in the free space between optical surfaces. As the name “orthovanadate” implies, a vanadate crystal is used as the medium.
This term “vanadate laser” may sound familiar. Vanadate lasers have been widely used for years. This older crystal gain medium might be considered conventional by some – other laser technologies that have since been released were designed to last longer and deliver better results, especially in industrial environments where the vanadate was limited to lower average power applications. The vanadate crystal essentially became a consumable item: it was known for having issues with clouding that would cause the laser to fail, hence a short lifespan. The multi-emitter laser diode design creates more heat and therefore limits the operation of the laser.
Oscillator: Fiber Laser
Laser Type: Fiber
Gain Medium: Fiber-doped Ytterbium
Laser Beam Propagation: Fused within a fiber
Fiber lasers were designed to correct those lifespan and reliability issues of the vanadate. Instead of having optical surfaces that can get dirty or fall out of alignment, the fiber laser has all optical surfaces fused into a fiber optic cable. Those optical surfaces, known as Bragg gratings, seal in the laser resonator, reflecting particular wavelengths of light and transmitting all others.
MOPA Laser: Fiber Oscillator + Amplifier
Now that we understand the two oscillators being combined, the next component to understand is “MOPA.” MOPA (Master Oscillator Power Amplifier) refers to a configuration consisting of a master fiber laser and an added amplifier to boost the output power. When MOPA architectures are used for pulsed laser sources, the amplifier may be used as a reservoir of energy. This amplifier makes it easier to obtain certain features with a master oscillator. You can then change the pulse duration as needed for different applications.
Do Hybrid Lasers Live up to the Hype?
Hybrid lasers promise new benefits: whereas in the past, one laser could be good for high peak power and beam quality but poor on output and service life, now you should be able to achieve all of those goals with the same unit.
Right?
If you’ve ever thought through the implications of a concept like “car-boat-plane,” then you know that beyond the initial “cool” reaction, the hybrid that tries to be everything can end up being, well, less than expected. The hype often doesn’t live up to reality.
The key is finding the best fit for your specific application and your operation. To learn more, take a look at hybrid lasers and how they work.