Lasers & Holography

Because I'll be WAY too busy at midnight, here's a celebratory laser show video for your new year pleasure!

As I mentioned back in this post, I've gone green.

The laser arrived today and I've been testing it all afternoon by terrorizing cats (not really) and airplanes (not really).

The laser is an OEM unit that's been customized by one of the true laser geeks from Photon Lexicon.

It's got a custom controller that allows the output power to be set from 0-100+mW although I likely won't be pushing it that hard.

Ok, so I didn't post a video link last Friday. Here's a video of lasers and Magic! I used to be really into magic so this is a perfect combination to me.

The magician is Jason Latimer and was apparently performing at the Magic Castle

It's been a busy year in a number of way which is why I haven't been posting too many lab updates and tutorials.

I've got a number of tutorials in the pipeline and pictures that need taking but the next two weeks promise to be just as full so I'm not sure how much I'll be able to get to while I've got the time off my "day job." We'll see though.

Click through for some pictures and descriptions of what I've been up to.

Researchers at NIST have developed a simpler method to "clean" carbon nanotube structures using an excimer laser.

In a forthcoming issue of Chemical Physics Letters, the NIST/NREL team describes how pulses from an excimer laser greatly reduce the amount of carbon impurities in a sample of bulk carbon single-walled nanotubes, without destroying tubes. Both visual examination and quantitative measurements of material structure and composition verify that the resulting sample is "cleaner". The exact cleaning process may need to be slightly modified depending on how the nanotubes are made, the authors note. But the general approach is simpler and less costly than conventional "wet chemistry" processes, which can damage the tubes and also require removal of solvents afterwards.

NIST researchers have come up with a new method that may help to identify defects in superconductors, using a lattice of laser beams controlling a Bose-Einstein condensate.

The JILA experiments were performed with 3 million rubidium atoms held in a magnetic trap. A superfluid of vortices was created by spinning the trap. The reddish BEC cloud, about 100 micrometers in diameter, contained about 100 hollow vortices, like a spinning bundle of fibers. Lasers were used to set up optical lattices grids of light in an arrangement of energy peaks and troughs in triangular and square patterns and focus them onto the BEC.

Because BECs and optical lattices can be precisely controlled, the technique may be useful in studying more mysterious patterned superfluids, such as superconductors.

Continue reading "Identifying defects using laser lattices"

Photonics.com reports that several groups have developed methods of cooling mirrors using not much more than beams from lasers. The research is aimed at revealing quantum effects in our macroscopic world.

Cooling occurs when photons bounce off a springlike structure with a natural resonant frequency. If a laser is off that frequency, the light acts like an ultracold viscous fluid, damping movement and, therefore, cooling the structure. The key to achieving the lowest possible temperature is to have a low-mass, highly reflective mirror mounted on a springy structure of high mechanical quality.

You can now buy holograms directly from us by going to http://www.hologramstore.biz. We accept COD, Paypal and credit card orders for a wide range of holograms.

Stop it. Stop it now.

If you know someone who's recently bought a laser pointer (of any kind) please take the time to make sure that they know not to point the thing at aircraft (really, any other person).

It doesn't matter that most pointer beams will expand too much to be any danger to the pilots, it doesn't matter if the power levels are too low to be of any real concern.

This is no joke. The more often that this sort of thing happens, the more likely it becomes that our lasers will become so regulated here in the US that even we can't get hold of decent power levels anymore.

What prompted this public service announcement?

Recently authorities raided a house in CA looking for a laser that's been shone at aircraft in the area. Particularly aircraft attempting to land at the Mineta International Airport.

"We received several calls from the FAA and also from some citizens stating that there was a green laser emanating from a residence pointing at some commercial airliners," said Serge Palanov, spokesman from the Santa Clara Sheriff's Department. "Our own helicopter -- Star One -- went up in the air into vicinity and they also experienced this green laser pointing at them."

Small lasers, used commonly as light pointers, can beam a high intensity light over a long distances. If the beam were to strike a pilot's eyes, it could blind him or her.

It doesn't matter that "small lasers, commonly used as light pointers" would NOT blind a pilot at the distances involved when some random individual gets lucky enough to scan an airliner by hand or that the description is needlessly alarmist. Trying to hit an aircraft with your laser pointer just isn't a good idea.

If you know someone who has been doing this, go give them a good smack and take their laser away.

I just (literally) took the plunge and purchased a Coherent 315M for the lab.

It should arrive next week which will be perfect timing for my holiday break.

I'd never heard of the band Flaming Lips before (I must remember to get out of the lab more often) but ran across this video from one of their concerts.

They apparently gave everone in the audience a laser pointer and then tossed a ball into their midst and encouraged the audience members to lase away.

Cool.

This development may just revolutionize the way and speed with which virus strains are identified in the field, using a combination of nanorod arrays and lasers.

Researchers Yiping Zhao, Sarat Shanmukh, Yongjun Liu, Les Jones, Richard A. Dluhy, and Ralph A. Tripp have developed a method of creating a silver nanorod array that acts as surface-enhanced Raman scattering substrate which allows microbe detection within a minute. Much faster than traditional chemical methods.

Among the biosensing methods being explored in virus research, surface-enhanced Raman spectroscopy (SERS) has received interest over the past few years due to its ability to detect even single molecules at the same time as providing structural and quantitative information about the analytes. It has been used to detect bacteria and viruses using either direct spectroscopic characterization or reporter-molecule-sandwich assemblies.

They use a method of fabrication that results in rods created at an oblique angle that aids in the scattering used to detect the microbes.

For the OAD method, we tilted the substrate such that the vapor arrives at close to the grazing angle. This process results in the preferential growth of nanorods on the substrate in the direction of deposition, due to a shadowing effect. Figure 1 shows scanning electron microscope (SEM) images of the optimal SERS substrates that we grew. The overall length of the nanorods was 868 ±95nm, while the diameter of the nanorods was 99±29nm. We calculated the density of the nanorods to be 13.3 ± 0.5rods/μm2 and the average tilt angle 71.3 ± 4.0°.

Additional links after the jump.

Frank DeFreitas took some time this past weekend to interview me about my holographic work, online store, involvement with the holography forum and other subjects.

Thanks Frank, it was a pleasure.