Green Laser Question: Explaining the Double Pumping Method

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In summary, the conversation discusses the discovery of a red laser diode inside a green laser. The speaker also shares their surprise at finding a cylinder that can turn red laser light into green laser light. They mention reading about a double pumping method and a non-linear optic that can convert red wavelength into green. The speaker is seeking an easy explanation to share with their students. They also express amazement at the advancements in technology, particularly the affordability of this device. The conversation ends with the speaker mentioning that the cylinder can also produce white light when turned backwards.
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omega-centauri
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I took apart my green laser, and found a red laser diode inside! Even stranger, I found a little cylinder that fit over the laser that normally would have thought to be a filter, but when I put it on the red laser, green laser light came out! I was totally stumped as to how this worked, but then read something about a double pumping method and the filter is really a set of two crystals that turn the red wavelength into green, but I was wondering if anyone had an easy explanation for this that I can share with my students? I didn't know you could change the wavelength (like cut it in half) like this! It's totally amazing what we can do these days, especially for under $10!

Oh and I should add that when I turned the filter-looking cylinder around and put it in backwards, white light reflected back in the direction of the diode... !
 
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omega-centauri said:
I took apart my green laser, and found a red laser diode inside! Even stranger, I found a little cylinder that fit over the laser that normally would have thought to be a filter, but when I put it on the red laser, green laser light came out! I was totally stumped as to how this worked, but then read something about a double pumping method and the filter is really a set of two crystals that turn the red wavelength into green, but I was wondering if anyone had an easy explanation for this that I can share with my students? I didn't know you could change the wavelength (like cut it in half) like this! It's totally amazing what we can do these days, especially for under $10!

Oh and I should add that when I turned the filter-looking cylinder around and put it in backwards, white light reflected back in the direction of the diode... !

The thing in front is a non-linear optic. When you drive the atoms in this crystal very hard, they do not respond linearly to the oscillating electric field, and you get out frequencies that are 2x the driving frequency. With these kinds of crystals, the effect is observable in only certain directions.

With other crystals, you can get sum frequency mixing.

Google "nonlinear optics" to see more about this.
 
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Related to Green Laser Question: Explaining the Double Pumping Method

1. What is the double pumping method used for in green lasers?

The double pumping method is used to increase the efficiency and power output of green lasers. It involves using two different pump sources, typically a diode laser and a flashlamp, to excite the lasing medium simultaneously. This results in a higher population inversion and therefore a stronger laser output.

2. How does the double pumping method work?

The double pumping method works by combining the advantages of two different pump sources. The diode laser provides continuous pumping, while the flashlamp provides a short but intense pulse of energy. This combination allows for a more sustained and efficient excitation of the lasing medium, resulting in a stronger and more stable laser output.

3. What are the benefits of using the double pumping method?

The double pumping method offers several benefits, including increased efficiency, higher power output, and improved stability of the laser output. It also allows for a wider range of lasing materials to be used, as different materials respond better to different pump sources. This method is commonly used in green lasers because it addresses the challenges of creating a strong and stable green laser beam.

4. Are there any drawbacks to using the double pumping method?

One potential drawback of the double pumping method is the increased complexity and cost of the laser system. Using two different pump sources requires more precise alignment and control, which can be challenging and expensive. Additionally, the use of a flashlamp can result in a shorter lifespan for the pump source compared to a diode laser.

5. How does the double pumping method differ from other methods of creating green lasers?

The double pumping method differs from other methods, such as frequency doubling or sum frequency generation, in that it directly excites the lasing medium rather than converting light from another source. This allows for greater control and efficiency in producing a green laser beam. Additionally, the double pumping method can be used with a wider range of lasing materials compared to other methods.

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