#light diffraction

What autumn means to me;

Autumn is one of my favorite times of the year honestly. The colors of the leaves changing and falling paired with the crisper air and darker skies brings me so much joy!! I'm glad that I've been able to enjoy the fall more since graduating high school because during those years, fall just meant school going back - I thoroughly hated high school. Now, I get to actually go outside and feel and breathe the cooler air and appreciate the beauty of the season.

With me being in university now, autumn is the perfect time to romanticize studying with a nice hot drink - something I've never had time to do before this year. I'm allowing myself to enjoy learning without associating it with tests, and it's been everything to me.

I don't have any new study pics to share with this, but I did catch a Perfect light diffraction moment on the wall in the physics building!!

From Earth Science Picture of the Day; September 22, 2018:

Encore - Iridescence and Corona Photographer: Fausto Lubatti; Summary Authors: Fausto Lubatti, Jim Foster

Today and every Saturday Earth Science Picture of the Day invites you to rediscover favorites from the past. Saturday posts feature an EPOD that was chosen by viewers like you in our monthly Viewers' Choice polls. Join us as we look back at these intriguing and captivating images.

While snowshoeing with friends on a beautiful winter's afternoon in the Val Biandino of northern Italy, I couldn't help but notice the striking iridescent clouds shown above. The slope of the valley effectively blocked the Sun, accentuating the iridescence or opalescence. Additionally, a colorful corona surrounding the Sun was easily visible. Cloud iridescence and coronas are both caused by diffraction processes. The mid-level clouds on the left side of the photo are formed by very fine droplets of similar sizes. These droplets deflect sunlight -- they interfere with light in such a way to produce patterns of colored rings. Note that the cumulus clouds at right (lower altitude) are composed of droplets of generally larger sizes and show no iridescence. Be sure to protect your eyes anytime you look in the vicinity of the Sun. Photo taken on January 5, 2013.

Photo Details: Camera Model: Canon EOS 5D Mark II; Lens: EF35mm f/2; Focal Length: 35.0mm; Aperture: f/13.0; Exposure Time: 0.0025 s (1/400); ISO equiv: 100; Software: GIMP 2.6.11.

Val Biandino, Italy Coordinates: 46.019853, 9.50458646

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From Earth Science Picture of the Day; June 18, 2018:

Science and a Cup of Tisane Photographer and Summary Author: Piero Armando

Sometimes it’s possible to do interesting experiences with very simple means. A few weeks back I was getting a cup of hot tisane and happened to notice the peculiar shape of the vapor from the cup, which was illuminated by the setting Sun. The rapidly rising vapor was forming beautiful swirls, due to flux turbulence. Additionally, iridescent colors could be detected as a result of diffraction of light by the tiny droplets composing the vapor. Photo taken on May 13, 2018.

Photo Details: Canon EOS 600D camera; 1/400 sec. exposure time; ƒ/7.1 aperture; ISO 800; 55 mm focal length.

Turin, Italy Coordinates: 45.0703, 7.6869

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From SpaceTelescope.Org Picture of the Week; June 4, 2018:

Threads of Blue

A ripple of bright blue threads through this galaxy like a misshapen lake system. The foreground of this image is littered with nearby stars with their gleaming diffraction spikes. A keen eye can also spot a few other galaxies that, while masquerading as stars at first glance, reveal their true nature on closer inspection.

The central galaxy streaked with color, IC 4870, was discovered by DeLisle Stewart in 1900 and is located approximately 28 million light-years away. It contains an active galactic nucleus, or AGN: an extremely luminous central region so alight with radiation that it can outshine the rest of the galaxy put together. AGNs emit radiation across the complete electromagnetic spectrum, from radio waves to gamma-rays, produced by the action of a central supermassive black hole that is devouring material getting too close to it. IC 4870 is also a Seyfert galaxy, a particular kind of AGN with characteristic emission lines.

IC 4870 has been imaged by Hubble for several studies of nearby active galaxies. By using Hubble to explore the small-scale structures of AGN in nearby galaxies, astronomers can observe the traces of collisions and mergers, central galactic bars, nuclear starbursts, jets or outflows, and other interactions between a galactic nucleus and its surrounding environment. Images such as this can help astronomers understand more about the true nature of the galaxies we see throughout the cosmos.

From Earth Science Picture of the Day; March 16, 2018:

Fogbow Over Northern Illinois Photographer: Lorraine Matti; Summary Authors: Lorraine Matti, Jim Foster

We had really dense fog in northern Illinois on the night of January 21 (2018), so I decided to have some fun and made the panoramic image above with the aid of the headlights on my Jeep. This lovely fogbow, accented by an oak tree and a pile of snow, results from diffraction of light (in this case headlights positioned at the antisolar point) in the minute water droplets composing the fog. Since diffraction, and not refraction, is the dominant scattering process, the bow is broader than a rainbow and nearly devoid of color. However, because the illuminating source here is quite bright and because evidently not all of the droplets are tiny, tints of color can be detected along the bow's outer edge.

Photo Details: Canon EOS 7D camera; 10 mm lens; ISO 800; 0.6 seconds exposure; 4 images stitched together in order to capture the entire bow. Software: Adobe Photoshop CC 2017 (Windows).

Hampshire, Illinois Coordinates: 42.0978, -88.5304

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From Earth Science Picture of the Day; February 27, 2017:

Iridescent Clouds Over Deventer, the Netherlands Photographer: Peter Paul Hattinga Verschure; Summary Authors: Peter Paul Hattinga Verschure, Jim Foster

The photo above shows unusual strongly iridescence in altocumulus wave clouds as observed over Deventer, the Netherlands. Iridescence is often noticed when mid-level clouds are observed in the vicinity of the Sun. The metallic colors result from diffraction processes -- when sunlight is scattered or deflected by the minute water droplets that compose these mid-level clouds. Note that colors are purer when the droplet sizes are uniform. Such uniformity in sizes is more likely to occur when the droplets form and or dissipate along the cloud edges. Always use extreme caution when looking anywhere near the Sun. Photo taken on January 6, 2017.

Photo Details: Camera Model: NIKON D80; Focal Length: 100.0mm (35mm equivalent: 150mm); Aperture: ƒ/16.0; Exposure Time: 0.0003 s (1/4000); ISO equiv: 200; Software: Adobe Photoshop Elements 8.0 Windows.

Deventer, Netherlands Coordinates: 52.2661, 6.1552

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 Photonics is the science and technology of light, with an emphasis on applications: harnessing light in a wide range of fields. The final day will be organized in collaboration with Assam science society Karimganj zone. The programme will be based on guiding light through various medium to innovative and spread light through nature. To celebrate this occasion one photographic exhibition will be organized, that will show the night sky and little photographic view on light travels through nature to illuminate our surrounding environment. Practical uses of Light-wave and technology will be displayed among the students. Light and technology basically deals with guiding electromagnetic radiation through different waveguides. This technology also involved in light wave technology or Photonics. Photonics is considered to be the physical science of light waves. It deals with the science behind the generation, detection and manipulation of light. A few talks will be arranged to show the nature of light and its dual nature that known as the wave-particle duality. It is to say that light has characteristics of both a continuous electromagnetic wave and a particle (photon). The day will be expected to celebrate with few technical and non-technical sessions. Light wave technology based invited talks will be arranged and additional talks will be given by departmental faculty member. The photographic display of night sky and a session of night sky observation will also be arranged for the benefit of our college students. 

The Active Learning in Optics Group in Department of Physics at Quaid-i-Azam university are going to organize a one day hands on workshop at Rawalpindi Women University with 4th Semester undergraduate girls student. We will start with oral presentation on ” Introduction to LASER followed by hands on sessions on: • Different kinds of light sources • Scattering of Light • Reflection, refraction, transmission and total internal reflection. • Proving laws of Geometrical optics, finding critical angle • Working principle of Fiber optics communication • Interference of light • Single and double slit diffraction • Measuring Stress with polarisers