Tag Archives: Industrial Microscopes

A Small Lesson in Multiphoton Microscopes

Maybe this is an excuse to show off these incredible images created with the Leica TCS SP8 MP, but why not take a look back at where this technology came from while we’re at it?

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What we’re seeing here is a 3D image with optical sectioning using a multiphoton microscope. The phenomenon behind this technology is called two-photon absorption (TPA). Essentially, two photons are absorbed at the exact same time in order to excite a molecule from one state to a higher energy electronic state. Thinking back to high school chemistry, light is given off once that molecule decays back to a lower state.

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Maria Goeppert-Mayer, the German-born American theoretical physicist, first predicted this process in her doctoral dissertation in 1931. It wasn’t until 30 years later, with the invention of the laser, that experimental verification for TPA was possible.

TPA was used as a spectroscopic tool until the 1980s. Once more developments in the field occurred, different applications were demonstrated. A few of them being photodynamic therapy, optical data storage, and imaging (obviously).

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Watt W. Webb is best known for suggesting using TPA for imaging and microscopy. In 1990 he co-invented mulitphoton microscopy along with Winfried Denk and Jim Strickler. Earlier in his career, Webb pioneered techniques in fluorescent correlation spectroscopy (FCS). The combination of TPA and FCS resulted in high resolution, high signal-to-noise images.

One of the biggest advantages to multiphoton microscopes is the use of long wavelength, low energy excitation lasers. This is less damaging to live cells and introduces fewer toxic effects. This unique attribute is responsible for the in vivo microscopy you’re seeing in these images. Developments in medical endoscopy are being explored since the potential for in vivo, in situ real-time diagnostics is there.

This concludes our small lesson in multiphoton microscopes. Class dismissed.

Buying a Microscope: What you need to know

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A lot of questions can arise when shopping for microscopes. Materials, lighting, lenses…These all determine what makes the best product for your purposes. Let this be an into to the basics to get you started.

Binocular and Monocular
When choosing between different types of microscopes, you will ask yourself, “What is better, binocular or monocular?” The answers will vary depending on your needs and budget. Binocular gives you more comfortable viewing for several hours at a time. If you need a microscope for children or students in brief sessions monocular may be a more cost effective choice,

Magnification
People often buy microscopes with too high magnification for their needs and can’t get the results they’re looking for. As a reference point, human blood cells are visible at x500 magnification. Depending on your requirements you may need even x1000 microscope, but x500 is usually enough for the majority of users.

Lighting
If a microscope has a built-in light, it uses either a fluorescent, tungsten or halogen bulb. Microscopes with fluorescent bulbs are usually the most expensive, however the light is brighter and produces less heat. Using an electric light on your scope is very convenient and useful, especially if you need a microscope for prolonged use.

Materials
If a microscope is made of plastic, don’t expect it to serve you for ages. When choosing a microscope, look for a sturdy metal alloy frame. It may be a bit more expensive, but it will stand up much better to consistent use. However, if you need to buy a microscope to be used by children, students, monocular microscope will be a better fit. In addition, it costs less in comparison to binocular.

These are just a few aspects to keep in mind when shopping for your ideal microscope. Check out our current specials, and complete product catalog to find the microscope that’s right for you.